Next-Generation Antennas E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 379

Veröffentlichungsjahr: 2021

Beschreibung

NEXT-GENERATION ANTENNAS: ADVANCES AND CHALLENGES

The first book in this exciting new series, written and edited by a group of international experts in the field, this exciting new volume covers the latest advances and challenges in the next generation of antennas.

Antenna design and wireless communication has recently witnessed their fastest growth period ever in history, and these trends are likely to continue for the foreseeable future. Due to recent advances in industrial applications as well as antenna, wireless communication, and 5G technology, we are witnessing a variety of developing and expanding new technologies. Compact and low-cost antennas are increasing the demand for ultra-wide bandwidth in next-generation (5G) wireless communication systems and the Internet of Things (IoT). Enabling the next generation of high-frequency communication, various methods have been introduced to achieve reliable high data rate communication links and enhance the directivity of planar antennas. 5G technology can be used in many applications, such as in smart city applications and in smartphones. This technology can satisfy the fast rise in user and traffic capacity in mobile broadband communications.

Therefore, different planar antennas with intelligent beamforming capability play an important role in these areas. The purpose of this book is to present the advanced technology, developments, and challenges in antennas for next-generation antenna communication systems. This book covers advances in next-generation antenna design and application domain in all related areas. It is a detailed overview of cutting-edge developments and other emerging topics and their applications in all areas of engineering that have achieved great accuracy and performance with the help of the advancement and challenges in next-generation antennas.

This outstanding new volume:

• Covers all the latest developments and future aspects of antenna communication
• Is concisely written, lucid, and comprehensive, practical application-based, with many informative graphics and schematics
• Will help students, researchers, as well as systems designers to understand fundamental antenna design and wireless communication
• Compares different approaches in antenna design

Leseprobe

Table of Contents

Cover

Title Page

Copyright

Preface

1 Different Types of Microstrip Filters for UWB Communication

1.1 Introduction

1.2 Previous Work

1.3 Conclusions

References

2 Design, Isolation Analysis, and Characterization of 2×2/4×4 MIMO Antennas for High-Speed Wireless Applications

2.1 Introduction

2.2 Understanding 2×2 MIMO Antenna Configuration

2.3 Diversity Performance Analysis of 2×2 UWB-MIMO/Dual-Polarization/UWB: Single, Dual, Triple, and Four Notched Bands

2.4 4×4 MIMO Antenna

2.5 Conclusions

References

3 Various Antenna Array Designs Using Scilab Software: An Exploratory Study

3.1 Introduction

3.2 Scilab: An Open-Source Software Solution

3.3 Antenna Array Design Using Scilab: Codes and Results

3.4 Conclusions

References

4 Conformal Wearable Antenna Design, Implementation and Challenges

4.1 Introduction

4.2 Conformal Antenna

4.3 Characteristics of Conformal Antenna

4.4 Design Methodology - Antenna Modeling

4.5 Wearable Conformal Antenna

4.6 Textile and Cloth Fabric Wearable Antennas

4.7 Design of Liquid Crystalline Polymer (LCP) Based Wearable Antenna

4.8 Result Discussion and Analysis

4.9 Challenges and Future Needs

4.10 Conclusion

References

5 Design and Analysis of On-Body Wearable Antenna with AMC Backing for ISM Band Applications

5.1 Introduction

5.2 Design of Star-Shape with AMC Backed Structure

5.3 Discussion of Results of Star-Shaped Antenna with AMC Structure

5.4 On-Body Placement Analysis of Proposed Antenna with AMC Structure

5.5 Transmitting Signal Strength

5.6 Conclusion

References

6 Antenna Miniaturization for IoT Applications

6.1 Introduction

6.2 Issues in Antenna Miniaturization

6.3 Antenna for IoT Applications

6.4 Miniaturize Reconfigurable Antenna for IoT

6.5 Conclusion & Future Work

References

7 Modified Circular-Shaped Wideband Microstrip Patch Antenna for Wireless Communication Utilities

7.1 Overview of Wireless Communication

7.2 Introduction to Microstrip Patch Antenna

7.3 Literature Review

7.4 Design and Implementation of Projected Antenna

7.5 Results and Discussion

7.6 Parametric Analysis

7.7 Summary

References

8 Reconfigurable Antenna for Cognitive Radio System

8.1 Introduction

8.2 Antenna

8.3 Antenna Reconfigurations

8.4 Uses and Drawbacks of Reconfigurable Antenna

8.5 Spectrum Access and Cognitive Radio

8.6 Cognitive Radio

8.7 Spectrum Sensing and Allocation

8.8 Results and Discussion

8.9 Conclusions

References

9 Ultra-Wideband Filtering Antenna: Advancement and Challenges

9.1 Introduction

9.2 Ultra-Wideband Filtering Antenna

9.3 Ultra-Wideband Filtering Antenna with Notch Band Characteristic

9.4 Conclusions

References

10 UWB and Multiband Reconfigurable Antennas

10.1 Introduction

10.2 Need for Reconfigurable Antennas

10.3 RF PIN Diode and MEMS Switch as Switching Devices

10.4 Triple Notched Band Reconfigurable Antenna

10.5 Tri-Band Reconfigurable Monopole Antenna

10.6 Conclusions

References

11 IoT World Communication through Antenna Propagation with Emerging Design Analysis Features

11.1 Introduction

11.2 Design and Parameter Analysis of Multi-Input Multi-Output Antennas

11.3 Measurement Analysis in 3D Pattern with IoT Module

11.4 Comparison of Antenna Design Concerning the IoT Data Transmission

11.5 Conclusions

Acknowledgement

References

12 Reconfigurable Antennas

12.1 Introduction

12.2 Reconfigurability of Antenna

12.3 Polarization Reconfigurable Antenna (RA)

12.4 Compound Reconfigurable Antennas (RAs)

12.5 Reconfigurable Leaky Wave Antennas

12.6 Reconfigurable Antennas - Applications in Wireless Communication

12.7 Optimization, Control, and Modeling of Reconfigurable Antennas

12.8 Conclusions

References

13 Design of Compact Ultra-Wideband (UWB) Antennas for Microwave Imaging Applications

13.1 Introduction

13.2 Microwave Imaging

13.3 Antenna Design Implementation

13.4 Design of a UWB-Based Compact Rectangular Antenna

13.5 Validation of the Miniaturized UWB Antenna with the Human Breast Model Developed

13.6 Conclusions

References

14 Joint Transmit and Receive MIMO Beamforming in Multiuser MIMO Communications

14.1 Introduction

14.2 System Model: Proposed Mimo Beamforming Architecture

14.3 Mimo Beamforming Based on Generalized Least Mean (GLM) Algorithm

14.4 Mean and Mean Square Stability of the GLM

14.5 Simulation Results

14.6 Summary

References

15 Adaptive Stochastic Gradient Equalizer Design for Multiuser MIMO System

15.1 Introduction

15.2 Related Literature Review

15.3 System Model

15.4 Derivation for the Probability of Error

15.5 Design of Adaptive Equalizer by Minimizing BER

15.6 Simulation Results

15.7 Summary

References

About the Editors

Index

End User License Agreement

List of Tables

Chapter 1

Table 1.1 Summary of multiband filters.

Table 1.2 Summary of ultra-wideband filters.

Table 1.3 Summary of ultra-wideband filters with notched band.

Chapter 2

Table 2.1 Tabulated diversity performance.

Table 2.2 Diversity performance comparison of 2×2 UWB and Multiband MIMO Antenna...

Table 2.3 Dual polarization MIMO antenna.

Table 2.4 UWB single/dual/triple/four notched bands 2×2 MIMO antenna.

Table 2.5 Comparison of 4×4 MIMO antenna configuration.

Chapter 3

Table 3.1 Learning Outcomes of antenna engineering course.

Chapter 4

Table 4.1 Dimension parameter of the patch.

Table 4.2 Density and thickness of arm tissues mass [31].

Table 4.3 Arm tissues parameters at distress signal frequency (0.406GHz) [31].

Table 4.4 Dimensions of the proposed planar antenna.

Chapter 5

Table 5.1 Variables of the designed antenna and AMC.

Chapter 7

Table 7.1 Simulated results of the antenna at different stages (Antenna 1, Anten...

Table 7.2 Comparison of Projected Antenna with few published multi-band antennas...

Chapter 8

Table 8.1 Comparison of impedance bandwidth for the three switching.

Chapter 9

Table 9.1 Summary of ultra-wideband filtering antenna.

Table 9.2 Summary of ultra-wideband filtering antenna with notch band characteri...

Chapter 10

Table 10.1 Comparison of an RF PIN diode and MEMS switch.

Table 10.2 Reconfigurable characteristics of reconfigurable notched band super w...

Table 10.3 Comparison of notched band reconfigurable monopole antennas.

Table 10.4 Multiband reconfigurable antenna.

Chapter 13

Table 13.1 Design parameters of antipodal slotted bowtie antenna [23].

Table 13.2 Optimal dimensions of the miniaturized UWB antenna design.

Guide

Cover

Table of Contents

Title Page

Copyright

Preface

Begin Reading

Index

End User License Agreement

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Scrivener Publishing100 Cummings Center, Suite 541JBeverly, MA 01915-6106

Advances in Antenna, Microwave, and Communication Engineering

Series Editors: Manoj Gupta, PhD, Pradeep Kumar, PhD

Scope: This book series represents an exciting forum for the presentation and discussion of the most recent advances in the antenna, microwave, and communication engineering area. In addition to scientific books, contributions on industrial applications are strongly encouraged, covering the above listed fields of applications. This book series is aimed to provide monograph, volumes, comprehensive handbooks and reference books that are empirical studies, theoretical and numerical analysis, and novel research findings for the benefit of graduate and postgraduate students, research scholars, hardware engineers, research and development scientists, and industry professional working towards the latest advances in antenna, microwave, and communication engineering and for their industrial applications.

Publishers at ScrivenerMartin Scrivener ([email protected])Phillip Carmical ([email protected])

Next-Generation Antennas

Advances and Challenges

Edited by

Prashant Ranjan,

Dharmendra Kumar Jhariya,

Manoj Gupta,

Krishna Kumar,

and

Pradeep Kumar

This edition first published 2021 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA© 2021 Scrivener Publishing LLCFor more information about Scrivener publications please visit www.scrivenerpublishing.com.

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Library of Congress Cataloging-in-Publication Data

ISBN 9781119791867

Cover image: (Antenna Tower): Carmen Hauser | Dreamstime.comCover design by Kris Hackerott

Set in size of 11pt and Minion Pro by Manila Typesetting Company, Makati, Philippines

Printed in the USA

10 9 8 7 6 5 4 3 2 1

Preface

In the 21st century, the world is facing many challenges and developments. People moving into urban areas are keen to experience the new changes in cities, where facilities are more user-friendly and comfortable. It has led to the existence of next-generation antennas, and researchers in this field are working towards developing these antennas for industrial applications. Keeping this in view, the present book is aimed at exploring the various aspect of next-generation antennas, and their advances, along with their challenges, in detail.

Antenna design and wireless communication have recently witnessed their fastest growth period ever in history, and this trend is likely to continue for the foreseeable future. Due to recent advances in industrial applications as well as antenna, wireless communication and 5G, we are witnessing a variety of new technologies being developed. Compact and Low-cost antennas are increasing the demand for ultra-wide bandwidth in next-generation (5G) wireless communication systems and the Internet of Things (IoT). Enabling the next generation of high-frequency communication, various methods have been introduced to achieve reliable high data rate communication links and enhance the directivity of planar antennas. 5G technology can be used in many applications such as smart city and smartphones, and many other areas as well. This technology can also satisfy the fast rise in user and traffic capacity in mobile broadband communications.

Therefore, different planar antennas with intelligent beamforming capability play an important role in these areas. The purpose of this book is to present the advanced technology, developments, and challenges in antennas for next-generation antenna communication systems. This book is concerned with the advances in next-generation antenna design and application domain in all related areas. It includes a detailed overview of the cutting age developments and other emerging topics, and their applications in all engineering areas that have achieved great accuracy and performance with the help of the advances and challenges in next-generation antennas.

Readers

This book is useful for the Researchers, Academicians, R&D Organizations, and healthcare professionals working in the area of Antenna, 5G Communication, Wireless Communication, Digital hospital, and Intelligent Medicine.

The main features of the book are:

• It has covered all the latest developments and future aspects of antenna communication.

• Very useful for the new researchers and practitioners working in the field to quickly know the best performing methods.

• Provides knowledge on advanced technique, monitoring of the existing technologies and utilizing the spectrum in an efficient manner.

• Concisely written, lucid, comprehensive, application-based, graphical, schematics, and covers all aspects of antenna engineering.

Chapter OrganizationChapter 1 gives an overview of Microstrip filters for UWB communication. It also describes the Multiband Microwave filter, Ultra-Wideband (UWB) bandpass filter, and ultra-wideband filter with notch band characteristic. Chapter 2 describes the introduction of 2×2 MIMO antenna configuration, and their diversity performance analysis.

Chapter 3 explains the Scilab open-source software and antenna array design.

Chapter 4 gives an overview of conformal antenna, explains characteristics of conformal antenna, wearable technology, cloth fabric wearable antennas, and simulated radiation pattern.

Chapter 5 gives an overview of On-Body wearable antenna for ISM band applications, explains design of star-shape with AMC backed structure, characterization of AMC unit cell, bending analysis of star-shaped antenna with AMC backed structure, and on-body placement analysis of the antenna with AMC structure.

Chapter 6 gives an overview of antenna miniaturization for IoT applications, issues in antenna miniaturization, antenna for IoT applications, and miniaturize reconfigurable antenna for IoT.

Chapter 7 gives an overview of wireless communication, Microstrip patch antenna, design & implementation of projected antenna, and observe the effect of different substrate materials.

Chapter 8 provides understanding of reconfigurable antenna for cognitive radio system, uses and drawbacks of reconfigurable antenna, and spectrum access and cognitive radio.

Chapter 9 describes the Ultra-Wideband filtering antenna, and Ultra-Wideband filtering antenna with notch band characteristic.

Chapter 10 describes the UWB and multiband reconfigurable antennas, need for reconfigurable antennas, triple notched band reconfigurable antenna, and tri-band reconfigurable monopole antenna.

Chapter 11 highlighted the IoT world communication through antenna propagation with emerging design analysis features, design and parameter analysis of multi-input multi-output antennas, measurement analysis in 3D pattern with IoT module.

Chapter 12 gives an overview of reconfigurable antennas, polarization reconfigurable antenna, compound reconfigurable antennas, and reconfigurable leaky wave antennas.

Chapter 13 gives an overview of design of compact Ultra-Wideband (UWB) antennas for microwave imaging applications, design of a UWB-based compact rectangular antenna, and validaed the miniaturized UWB antenna with the human breast model developed.

Chapter 14 gives an overview of joint transmit and receive MIMO beam-forming in multiuser MIMO communications, and system modeling for MIMO beamforming architecture based on generalized least mean algorithm.

Chapter 15 describes the adaptive stochastic gradient equalizer design for multiuser MIMO system, and design of adaptive equalizer by minimizing BER.

1Different Types of Microstrip Filters for UWB Communication

Prashant Ranjan1*, Krishna Kumar2, Sachin Kumar Pal3 and Rachna Shah4

1Department of ECE, University of Engineering and Management, Jaipur, India

2UJVN Ltd., Uttarakhand, India

3Bharat Sanchar Nigam Ltd., Guwahati, India

4National Informatics Centre, Dehradun, India

Abstract

Many filters such as triple-band filter, multiband filter, UWB filter, and notch band filters have been investigated in recent decades [1]. Bandpass filters with the features of good performance, micro-package, ease of use, and low cost have been the focus of device miniaturization. However, most of these UWB filters with band-notched have been designed by using various slots either in the ground plane or radiating patch, slit on feeding line, or integration of filter in feed line of the antenna. Slotted methods can be used for frequency rejection but it may distort the radiation patterns because of the electromagnetic leakage of these slots. In this chapter, a survey of multiband filter, UWB filter, and UWB with notch band filter are presented.

Keywords: Ultra-wideband, bandpass filter, microstrip patch, multiband, multiple-mode resonator, and transmission zeros

1.1 Introduction

The system can be streamlined and the physical dimension of the circuit minimized by triple-band microwave filters, thereby increasing the demand for triple-band microwave filters in modern communication systems. Recently, in many research papers, triple and multiband microwave filters have been widely studied. The use of alternately cascaded multiband resonators is one way of designing a triple-band filter. Coupling systems are used to achieve two and three frequency bands with Quasi-elliptic and Chebyshev frequency responses [2].

1.2 Previous Work

Various researchers have worked on the Microstrip filters for UWB communication.

1.2.1 Multiband Microwave Filter for a Wireless Communication System

Hao Di et al. [3] presented a technique to achieve a triple passband filter. In this method, a frequency transformation from the normalized frequency domain to the actual frequency domain is used. Applying this transformation, filter circuits with cross-coupling having triple-passband have been constructed. Cross coupled tri-band filter topology is presented, which consists of parallel resonators and admittance inverters. By using expressions, the external quality factors and coupling coefficients can be calculated. Three passbands 3.3–3.4, 3.5–3.6, and 3.7–3.8 GHz, with more than 20 dB return loss have been reported in this paper.

Hsu et al. [4] proposed asymmetric resonator-based one wideband and two tri-band BPFs. The resonator contains microstrip sections with different electrical lengths. Three resonant modes can be shifted to the desired center frequencies by varying the stub length of the first filter. In the second filter, asymmetrical resonators are used to achieve a wide stopband. For the third filter, wideband BPF is designed using multi-mode resonances and transmission zeros (TZs) of the asymmetrical resonator. It suppressed the higher-order harmonics. The three passbands 1.5, 2.5, and 3.5 GHz are achieved using four resonators.

Liou et al. [5], proposed a Marchandbalun filter with the shorted coupled line to achieve triple passbands. The filter is constructed with a triple-band resonator to exhibit the triple-band admittance inverter characteristic. The compensation techniques for phase–angle and impedance matching are used to improve the phase and amplitude responses of the existing three passbands. The defected ground structure stubs and microstrip coupled–line sections is used to realize the filter. Jing et al. [6] proposed a single multimode resonator-based filter with six passbands. The proposed MMR is a SIR (stepped impedance resonator) with two symmetrical open-circuited stubs positioned at two sides and one shorted stub connected in the middle. The electrical lengths of two open stubs are increased to excited the transmission zeros (TZs) and transmission poles (TPs). The TZs are separated from TPs by introducing open stubs; therefore, a six-band BPF is designed. Two input-output tapped branches and radical stub-loaded shorted lines are adjusted to improve filter performance.

Hong et al. [7] proposed a cross-coupled microstrip filter by using square open-loop resonators. In this paper coupling coefficients calculation of the three coupling structures of filters is developed. Empirical models are presented to estimate the coupling coefficients. A four-pole elliptic function type filter is designed. Three types of coupling characteristics,the electric, magnetic, and mixed couplings, have been reported. Kuo et al. [8] presented a microstrip filter with two frequency passband response based on SIR. SIR is in parallel-coupled and vertical–stacked configuration. Resonance characteristics of the second resonant frequency can be tuned over a wide range by adjusting its structure parameters. Tapped input/output couplings are used to match–band response for the two designated passbands. Both coupling length and gap are adjusted together to meet the required coupling coefficients of two bands. Fractional bandwidth design graphs are used to determine geometric parameters. Two passband resonant frequencies are 2.45 and 5.8 GHz with a fractional bandwidth of 12% and 7%, respectively. The measured insertion loss for the first passband is 1.8 dB and for the second passband is 3.0 dB. Higher-order filters are also designed using this design procedure.

Guan et al. [9] proposed a triple-band filter using two pairs of SIRs having single transmission zero. The first and the third frequency bands are realized by using Parallel coupled microstrip lines and the second frequency band is realized by using an end-coupled microstrip line. Single TZ is generated due to the antiparallel structure of the microstrip line. 2.4 GHz and 5.7 GHz are generated by longer resonators and 3.8 GHz is generated by the shorter resonators. By changing the impedance ratio of the resonator, the passband position of the filter can be adjusted. The filter bandwidths can be adjusted by adjusting the distance between resonators.

Ko et al. [10] presented two coupled line structures with open stubs to design a triple-band filter but insertion losses and bandwidths are poor. The third resonance frequency is shifted from 8.9 GHz to 6.5 GHz by variation in the lengths of two open stubs. A gap between transmission lines is used to adjust the second resonance frequency at 4.2 GHz. The first resonance frequency (2.4 GHz) can be adjusted using the coupled line length.

Lin et al. [11] proposed a triple-band BPF based on SIR. Hairpin type structure is used to reduce the size of the filter. Three passbands are 1.0, 2.4, and 3.6 GHz with an insertion loss of 2.2, 1.8, and 1.7 dB, respectively. Wibisonoet et al. [12] proposed a triple band BPF using cascaded three SIR. Filter passband frequencies are 900 MHz, 1800 MHz, and 2600 MHz simultaneously. Riana et al. [13] proposed a split-ring resonator to create three passband frequencies having two TZs. The filter coupling model approach is used to design filter and control passbands. Additional transmission zeros can be introduced by adjusting the position of the coupled resonators. Using triple-mode SRRs two filter topologies have been described. Using the lumped-element model to design the mainline and cross-couplings topology is presented in this paper. Two independent extraction methods, a de-tuning method, and a parameter-extraction method are used to determine coupling coefficients. Three passbands are 1.7, 2.4, and 3 GHz.

Liu et al. [14] proposed a triple band HTS (high temperature superconducting) filter using stub–loaded multimode resonator. The odd-even mode method is used to investigate the characteristics of the multimode resonator. A nonresonant node with a source-load coupling configuration is used to create TZs. Three passband resonant frequencies of the HTS filter, 2.45, 3.5, and 5.2 GHz, are presented. Insertion losses of the first, second, and third passbands are 0.16 dB, 0.55 dB, and 0.22 dB, respectively. The overall size of the filter is 8.3 mm × 8.6 mm. Qiang et al. [15] proposed a design of a wideband 90° phase shifter, which consists of open stub-based stepped impedance and a coupled–line to achieve wideband. The impedance ratio of the SIOS is used to analyze the bandwidths of return loss and the coupling strength of the coupled–line is used to analyze the phase deviation. The bandwidth of the phase shifter is 105% (0.75 to 2.4 GHz) with an insertion loss of 1.1dB.

Haiwen et al. [16] presented a triple band HTS filter by using a multimode stepped impedance split ring resonator (SI–SRR) to achieve the wide stopband property. Even and odd mode analysis is used to analyze the equivalent circuit model. This filter can be operated at 2 GHz, 3.8 GHz, and 5.5 GHz. The measured insertion losses can be obtained as approximately 0.19 dB, 0.17 dB, and 0.3 dB respectively at the center frequency of each passband. Zheng et al. [17] proposed a UWB BPF by creating triple notch-bands to make the multiband filter. SIR and four shorted stubs having a length of λ/4 are used to design the basic UWB filter. Open load stubs and E–shaped resonator are used to achieve triple band-notched performance. Three notched bands are at 4.8 GHz, 6.6 GHz, and 9.4 GHz. The minimum insertion loss of 0.6dB and a maximum ripple of 0.88 dB are reported.

Guan et al. [18] proposed a triple band HTS filter based on a coupled line SIR (C-SIR) to control transmission zeros. Three harmonic peaks are generated using C–SIR. Even–odd analysis method is applied to analyze the filter. An interdigital structure between the feed lines and C–SIR is used to increase the selectivity of the filter. Spiral-shaped lines are used for better coupling of the second-order resonator. Three frequency bands 1.57 GHz for GPS, 3.5 GHz for WiMAX, and 5.5 GHz for WLAN are achieved. Insertion losses are found to be 0.10, 0.20, and 0.66 dB at each passband, respectively.

Chen et al. [19] proposed multiband microstrip bandpass filters with circuit miniaturization. Five compact triple modes stub-load SIRs (SL–SIRs) are used to achieve five bands filter. The coupling scheme presented in this paper provides multiple paths for different frequency bands which gives more design flexibility. Centre frequencies of five bands are 0.6, 0.9, 1.2, 1.5, and 1.8 GHz. The insertion losses are approximately 2.8 dB, 2.9 dB, 2.9 dB, 2.6 dB, and 2.3 dB respectively. Wen et al. [20] proposed a six-band BPF based on semi-lumped resonators. The semi-lumped resonator included a chip inductor in the midpoint and two identical microstrip lines. Comparison between the semi-lumped resonator and conventional half-wavelength uniform resonator are presented. Harmonic frequencies are controlled by semi-lumped resonator. A distributed coupling technique is used to integrate bandpass filters. Low loading effects are achieved, which is essential for multiband circuits.

Wang et al. [23] proposed a compact UWB BPF having three notch bands by using a defected microstrip structure of U–shaped (UDMS). E–shaped MMR and interdigital coupled lines are used to obtain two transmission zeros at lower and upper passbands. The triple band-notched characteristics are achieved by introducing three parallel UDMSs. Notch band frequencies are 5.2, 5.8, and 8.0 GHz. A summary of previous work on multiband filters is given in the following Table 1.1.

1.2.2 Ultra-Wideband (UWB) Bandpass Filter

Wong et al. [27] proposed a UWB bandpass filter by using a quadruple–mode resonator. Two transmission zeros are generated by introducing two short-circuited stubs in MMR-based resonator. Two short-circuited stubs are used to control the fourth resonant mode and combining with the previous three resonant modes to make a quadruple–mode UWB filter. RT/Duroid 6010 substrate is used having a height of 0.635 mm, loss tangent 0.0023, and permittivity of 10.8. Interdigital coupled-lines are used to feed the MMR. Filter covers the frequency range of 2.8-11.0 GHz with a fractional bandwidth of 119%. Minimum insertion loss is found 1.1 dB within the UWB passband. Group delay Variation is found between 0.19 – 0.52 ns within UWB passband.

Table 1.1 Summary of multiband filters.

Xu et al. [28] presented a UWB bandpass filter with Koch island-shaped stepped impedance lines (SIL). A Koch fractal–shaped ring slot is cut in the ground plane of the filter to realize negative permittivity. The composite right/left-handed transmission line is arranged with the gap in the conductor strip to realize negative permeability. It included five-section SIL on each side with an asymmetrical structure. The passband frequency range is 2.5–11 GHz with a relative bandwidth of 126%. Deng et al. [29] proposed a quintuple–mode stub-loaded resonator-based ultra-wideband bandpass filter. Two odd modes and three even modes are generated. Stepped impedance open and short stub are used to adjust the even–mode resonance frequencies but the odd–modes are fixed. Two TZs near the lower and upper cutoff frequencies can be generated by the short stub. High resonant modes of the desired passband are adjusted by applying a low–impedance line of the MMR. The open stubs are used to improve the upper stopband transmission zero. The passband frequency range of the filter is 2.8–11.2 GHz. Group delay variation and insertion loss are achieved lower than 2 dB and less than 0.63 ns, respectively.

Hao et al. [30] proposed a UWB filter based on multilayer technology. A transmission zero at the upper stopband has been generated by designing a resonator on the middle layer. Lower stopband transmission zero has been generated by designing a shorted coupled line on the top layer. Multilayer liquid crystal polymer technology is used to fabricate the filter. Bandwidth from 3 to 9 GHz is achieved with a flat group delay. It is useful for wireless UWB systems. Chu et al. [31] proposed a UWB bandpass filter based on stub–loaded MMR.The MMR is loaded with three open stubs. A stepped–impedance stub is positioned at the center and two stubs at the symmetrical side are located. Three even modes, two odd modes, and two transmission zeros are generated by the stepped–impedance stub. The resonator is designed to locate the two odd modes within the UWB band. Parameters of the stepped–impedance stub at the center can be used to adjust the even modes only. Passband frequency is 3.1–11.1 GHz, with a fractional bandwidth of 117%. Group delay within the UWB passband is between 0.25–0.70 ns.

Zhang et al. [32] proposed a UWB filter by using shorted stepped impedance stubs cascaded with the interdigital coupled line. Four even modes and three odd modes are generated. Odd and even mode analysis is used to verify the circuit. UWB filter covers passband from 3.4 to 10.7 GHz. Zhu et al. [33] presented a UWB bandpass filter based on dual-stub-loaded resonators (DSLR). Two transmission zeros are generated at the lower and upper stopband by applying The DSLR. Lengths of the stubs can be used to control the bandwidth. The relative dielectric constant of substrate material used to fabricate is 2.55 with a loss tangent of 0.0019 and the height of the substrate is 0.8 mm. Fractional BW of the filter is 106% and insertion loss is less than 0.7 dB. Li et al. [34] proposed two UWB band-pass filters based on an improved model. This paper designed two UWB BPFs with a fractional bandwidth of 51% (3.1 to 5.2 GHz) and 108% (3 to 10 GHz). Four short-circuited stubs connected with transmission lines are included to improve the model. The first and fourth short-circuited stubs are used to generate two transmission zeros. Less than 3 dB insertion loss is found between 3.1 to 10 GHz and less than 0.4 dB is found between 3.1 to 5.2 GHz. The sizes of the filters are 19 mm × 14 mm and 15 mm × 15 mm, respectively. Matrix analysis and short-circuited stubs model with the improved distributed quarter wave is presented.

Saadi et al. [35] proposed a design technique to implement UWB bandpass filters based on an integrated passive device (IPD) technology. Hourglass filter theory and the inductors are included in the filter circuit with the zigzag method for miniaturization of the filter. The filter is designed in 0.18 μm CMOS technology. This filter exhibits enhanced selectivity and controllable transmission zeros. Design approaches to this filter can be divided into two groups. The first one has established an electrical circuit model and the second is manufacturing technologies. The electrical circuit model is used to obtain the filter electrical specifications that affect the filter’s physical aspects. Bandwidth covered the entire UWB spectrum. Taibi et al. [36] proposed, stepped–impedance open stub (SIS) based ultra-wideband bandpass filter. SIS is connected in the center of a uniform impedance transmission line. For coupling enhancement three interdigital parallel coupled-lines below aperture–backed are connected at each side of the filter. The frequency range of the filter is 3.2–11.1 GHz having a fractional bandwidth of 115%.

Janković et al. [37] proposed a defective ground structure-based UWB bandpass filter, which is used to connect a square patch with a ground plane to generate a resonant mode at a frequency lower than the without grounded patch resonator of two fundamental modes. Fundamental resonant frequencies can be controlled independently. By creating slots in the patch the higher modes resonant frequencies can be decreased. The Taconic CER10 substrate material is used with a relative dielectric constant of 9.8 and a thickness of 1.27mm. Group delay is 0.25 ns and insertion loss is less than 0.9 dB. Passband frequency for UWB band is 3.09–10.69 GHz. Yun et al. [38] proposed a particle swarm optimization (PSO) process to design a UWB bandpass filter. One cell CRLH–TL resonator, stepped impedance (SI), and two spur lines are used to design the UWB filter. The one-cell CRLH–TL resonator has a wide passband filtering characteristic.

The harmonics at the outside of the UWB band are removed by using one SI and two spur lines. Less than 1.4 dB flat insertion losses within passband and 11.5 to 22 GHz stopbands are achieved.

Sekaret et al. [40] proposed a slow-wave CPW based notch band UWB filter. The filter provided improved skirt rejection and better stopband rejection by DGS. DGS is used to achieve attenuation of the signal from 11 to 16 GHz. A notch is created by using a bridge structure to reject WLAN interference at 5.65 GHz. A summary of previous work on ultra-wideband filters is given in the following Table 1.2.

1.2.3 Ultra-Wideband Filter with Notch Band Characteristic

Rabbi et al. proposed [41] a UWB bandpass filter with a reconfigurable notched band to reject unwanted signals. A PIN diode is used as a switch for the notch. The filter has a notched band at 3.5 GHz when the switch is in the ON state. In the OFF state, a full band response is obtained. A third-order BPF consists of a single λg/2 resonator placed between two λg/4 short-circuited resonators. A grounded end is added with L–shaped parallel coupled transmission line to remove the undesired signal at 3.5 GHz. Zhao et al. [42] proposed a UWB bandpass filter using E–shaped resonator with two sharp notches. Genetic algorithm (GA) based UWB BPF is designed in which a set of structures as a chromosome and a structure as a gene is defined. The dual notch bands are generated by adjusting resonant frequencies of the E–shaped resonator. Two notches at 5.9 GHz and 8.0 GHz are obtained.

Song et al. [43] proposed a notched bands ultra-wideband bandpass filter based on triangular-shaped DGS. Transmission zeros are produced at a higher frequency by assigning six tapered defected ground structures. The low impedance microstrip is connected with short-circuited stubs to generate a TZ at the lower cut-off frequency. By increasing and folding the arm of the coupled-line to create a notch at 5.3 GHz, and create another notched band at 7.8 GHz by using a slot of the meander line. To achieve stronger coupling used quasi-IDC with slots on the ground plane. Sarkar et al. [44] proposed a UWB bandpass filter having high selectivity and dual notch bands. Short SLR and open stub are used to realize the UWB BPF. Meandered shorted stub is applied to the size of the filter. Two odd modes and two even modes excitations are present. Both modes are combined to achieve UWB BPF. Open stub loaded resonators (OSLR) are used to control the even mode frequencies and two transmission zeroes but odd mode frequencies are fixed. SLR is used to control the odd mode frequencies. Spiral resonators shaped slots of half-wavelength long are cut in the ground plane to obtained a notch band at 5.13 GHz. A notch at 8.0 GHz is achieved by adding an inward folded resonator near open SLR. Passband insertion loss is within 1.5dB. The notch bands eliminate the interference of WLAN and satellite frequency signal.

Table 1.2 Summary of ultra-wideband filters.

Chen et al.