Microwave Ring Circuits and Related Structures

"The reader will not only know the basic operation and theoretical equations but also understand how they are applied." (IEEE Circuits & Devices, July/August 2006) "All of the attractive features of the first edition have remained...the revised book covers ring resonators built in various transmission lines." (Microwave Journal, November 2004)

KAI CHANG, PhD, is the Raytheon E-Systems Endowed Professor in the Department of Electrical Engineering at Texas A&M University where he teaches and performs research in microwave devices, circuits, and antennas. In addition to publishing more than 400 technical papers and twelve books on microwave circuits, components, antennas and subsystems, Dr. Chang is an award-winning author, editor, and Fellow of the IEEE. His awards include a Special Achievement Award from TRW, the Halliburton Research Excellence Award, the Distinguished Teaching Award, and the Distinguished Research Award from Texas A&M. LUNG-HWA HSIEH is a doctoral student at Texas A&M University. He has authored more than fifteen papers on microwave ring circuits. He was previously a senior design engineer at General Instruments involved in RF design.

Preface. 1 Introduction. 1.1 Background and Applications. 1.2 Transmission Lines and Waveguides. 1.3 Organization of the Book. 2 Analysis and Modeling of Ring Resonators. 2.1 Introduction. 2.2 Simple Model. 2.3 Field Analyses. 2.3.1 Magnetic-Wall Model. 2.3.2 Degenerate Modes of the Resonator. 2.3.3 Mode Chart for the Resonator. 2.3.4 Improvement of the Magnetic-Wall Model. 2.3.5 Simplified Eigenequation. 2.3.6 A Rigorous Solution. 2.4 Transmission-Line Model. 2.4.1 Coupling Gap Equivalent Circuit. 2.4.2 Transmission-Line Equivalent Circuit. 2.4.3 Ring Equivalent Circuit and Input Impedance. 2.4.4 Frequency Solution. 2.4.5 Model Verification. 2.4.6 Frequency Modes for Ring Resonators. 2.4.7 An Error in Literature for One-Port Ring Circuit. 2.4.8 Dual Mode. 2.5 Ring Equivalent Circuit in Terms of G, L, C 35 2.5.1 Equivalent Lumped Elements for Closed- and Open-Loop Microstrip Ring Resonator. 2.5.2 Calculated and Experimental Results. 2.6 Distributed Transmission-Line Model. 2.6.1 Microstrip Dispersion. 2.6.2 Effect of Curvature. 2.6.3 Distributed-Circuit Model. References. 3 Modes, Perturbations, and Coupling Methods of Ring Resonators. 3.1 Introduction. 3.2 Regular Resonant Modes. 3.3 Forced Resonant Modes. 3.4 Split Resonant Modes. 3.4.1 Coupled Split Modes. 3.4.2 Local Resonant Split Modes. 3.4.3 Notch Perturbation Split Modes. 3.4.4 Patch Perturbation Split Modes. 3.5 Further Study of Notch Perturbations. 3.6 Split (Gap) Perturbations. 3.7 Coupling Methods for Microstrip Ring Resonators. 3.8 Effects of Coupling Gaps. 3.9 Enhanced Coupling. 3.10 Uniplanar Ring Resonators and Coupling Methods. 3.11 Perturbations in Uniplanar Ring Resonators. References. 4 Electronically Tunable Ring Resonators. 4.1 Introduction. 4.2 Simple Analysis. 4.3 Varactor Equivalent Circuit. 4.4 Input Impedance and Frequency Response of the Varactor-Tuned Microstrip Ring Circuit. 4.5 Effects of the Package Parasitics on the Resonant Frequency. 4.6 Experimental Results for Varactor-Tuned Microstrip Ring Resonators. 4.7 Double Varactor-Tuned Microstrip Ring Resonator. 4.8 Varactor-Tuned Uniplanar Ring Resonators. 4.9 Piezoelectric Transducer Tuned Microstrip Ring Resonator. References. 5 Electronically Switchable Ring Resonators. 5.1 Introduction. 5.2 PIN Diode Equivalent Circuit. 5.3 Analysis for Electronically Switchable Microstrip Ring Resonators. 5.4 Experimental and Theoretical Results for Electronically Switchable Microtrip Ring Resonators. 5.5 Varactor-Tuned Switchable Microstrip Ring Resonators. References. 6 Measurement Applications Using Ring Resonators. 6.1 Introduction. 6.2 Dispersion, Dielectric Constant, and Q-Factor Measurements. 6.3 Discontinuity Measurements. 6.4 Measurements Using Forced Modes or Split Modes. 6.4.1 Measurements Using Forced Modes. 6.4.2 Measurements Using Split Modes. References. 7 Filter Applications. 7.1 Introduction. 7.2 Dual-Mode Ring Bandpass Filters. 7.3 Ring Bandstop Filters. 7.4 Compact, Low Insertion Loss, Sharp Rejection, and Wideband Bandpass Filters. 7.5 Ring Slow-Wave Bandpass Filters. 7.6 Ring Bandpass Filters with Two Transmission Zeros. 7.7 Pizoeletric Transducer-Tuned Bandpass Filters. 7.8 Narrow Band Elliptic-Function Bandpass Filters. 7.9 Slotline Ring Filters. 7.10 Mode Suppression. References. 8 Ring Couplers. 8.1 Introduction. 8.2 180 Degrees Rat-Race Hybrid-Ring Couplers. 8.2.1 Microstrip Hybrid-Ring Couplers. 8.2.2 Coplanar Waveguide-Slotline Hybrid-Ring Couplers. 8.2.3 Asymmetrical Coplanar Strip Hybrid-Ring Couplers. 8.3 180 Degrees Reverse-Phase Back-to-Back Baluns. 8.4 180 Degrees Reverse-Phase Hybrid-Ring Couplers. 8.4.1 CPW-Slotline 180 Degrees Reverse-Phase Hybrid-Ring Couplers. 8.4.2 Reduced-Size Uniplanar 180 Degrees Reverse-Phase Hybrid-Ring Couplers. 8.4.3 Asymmetrical Coplanar Strip 180 Degrees