Impedance Transformers

Non

Advanced design of microwave power divider with enhanced harmonic suppression.

Ip, Wei Chi.Thesis (M.Phil.)--Chinese University of Hong Kong, 2011.Includes bibliographical references (leaves 92-94).Abstracts in English and Chinese.Abstract --- p.i摘要 --- p.iiAcknowledgement --- p.iiiTable of Content --- p.ivLists of Figures --- p.viiLists of Tables --- p.xiiChapter Chapter 1: --- Introduction --- p.1Chapter 1.1 --- Research Motivation and Obj ective --- p.1Chapter 1.2 --- Original Contribution --- p.2Chapter 1.3 --- Overview of the Thesis Organization --- p.3Chapter 1.4 --- "Research Approach, Assumptions and Limitations" --- p.4Chapter Chapter 2: --- Power Divider Design Fundamentals --- p.5Chapter 2.1 --- Power Divider Basics --- p.5Chapter 2.2 --- Wilkinson Power Divider --- p.6Chapter 2.3 --- Power Divider with Unequal Power Division --- p.8Chapter 2.4 --- Multi-way Power Divider --- p.9Chapter 2.4.1 --- Wilkinson N-way Hybrid --- p.10Chapter 2.4.2 --- Radial Hybrid --- p.11Chapter 2.4.3 --- Fork Hybrid --- p.12Chapter 2.4.4 --- Multi-layer Approach --- p.ISChapter 2.4.5 --- Power Recombination Concept --- p.15Chapter 2.4.6 --- Multi-coupled-line Approach --- p.18Chapter Chapter 3: --- Conventional Power Divider Designs with Harmonic Suppression --- p.20Chapter 3.1 --- Resonating-stubs Topology --- p.20Chapter 3.2 --- Asymmetric Defected Ground Structure (DGS) --- p.26Chapter 3.3 --- Anti-Coupled Line Structure --- p.30Chapter 3.4 --- Microstrip Electromagnetic Bandgap (EBG) Based Topology --- p.32Chapter 3.5 --- Embedded Resonators Topology --- p.37Chapter 3.6 --- Extended Line Approach --- p.39Chapter Chapter 4: --- New 2-way Power Divider Design with Spurious Suppression and Impedance Transformation --- p.41Chapter 4.1 --- Proposed Topology --- p.41Chapter 4.2 --- Design and Analysis --- p.42Chapter 4.3 --- Simulation Study --- p.45Chapter 4.4 --- Experimental Verification --- p.50Chapter 4.5 --- Summary --- p.57Chapter Chapter 5: --- New 2-way Power Divider Design with Extended Spurious Suppression --- p.58Chapter 5.1 --- Proposed Topology --- p.58Chapter 5.2 --- Design and Analysis --- p.59Chapter 5.3 --- Simulation Study --- p.64Chapter 5.3 --- Experimental Verification --- p.68Chapter 5.4 --- Summary --- p.71Chapter Chapter 6: --- New 2-way Unequal Power Divider Design with Dual-harmonic Rejection --- p.72Chapter 6.1 --- Proposed Topology --- p.72Chapter 6.2 --- Design and Analysis --- p.73Chapter 6.3 --- Simulation Study --- p.76Chapter 6.4 --- Experimental Verification --- p.77Chapter 6.4 --- Summary --- p.80Chapter Chapter 7: --- New 3-way Power Divider Design with Multi-harmonic Rejection..… --- p.81Chapter 7.1 --- Proposed Topology --- p.81Chapter 7.2 --- Design and Analysis --- p.82Chapter 7.3 --- Simulation Study --- p.85Chapter 7.4 --- Experimental Verification --- p.87Chapter 7.4 --- Summary --- p.90Chapter Chapter 8: --- Conclusion --- p.91References --- p.92Author's Publications and Awards --- p.95Chapter Appendix 1: --- ABCD Parameters of Some Useful Two-port Circuits --- p.96Chapter Appendix 2: --- More Designs of Proposed Configuration in Chapter 5 --- p.97Chapter A2.1 --- Miniaturized version of Example 1 --- p.97Chapter A2.2 --- Design with improved stop-band response --- p.101Chapter A2.3 --- Design of prototype with 2 GHz operating frequency --- p.104Chapter Appendix 3: --- Brief Summary of Power Dividers with Harmonic Suppression --- p.10

Analytical Approaches to Load Modulation Power Amplifier Design

In future mobile communication networks, there will be a shift toward higher carrier frequencies and highly integrated multiple antenna systems. The system performance will largely depend on the available radio frequency (RF) hardware. As such, RF power amplifiers (PAs) with improved performance, e.g. energy efficiency, are needed. Active load modulation (ALM) is one of the most common PA efficiency enhancement techniques. Unfortunately, different ALM techniques come at the cost of degrading other PA attributes. Through investigation of new ALM design techniques, the overall objective of this thesis is to improve upon different attributes and performance trade-offs in ALM PAs for future wireless systems.\ua0The working principle of ALM PAs is determined by both how the individual transistors are operated and how their outputs are combined. In the first part of the thesis, an analytical approach, where the output combiner is assumed to be an arbitrary black-box, is applied to the Doherty PA. The fundamental interaction between the main and auxiliary transistors is analyzed and generalized. New solutions with improved performance are identified, such as higher gain and an improved efficiency-linearity trade-off. This approach also introduces improved integration possibilities, which are demonstrated by a transmitter where the antenna acts as both the radiator and the Doherty combiner. Additionally, the analytical approach is applied to an isolated two-way power divider. This unlocks many new possibilities, such as improved integration and layout flexibility. \ua0In the second part, one embodiment of the emerging ALM architecture, the load modulated balanced amplifier (LMBA), is proposed: the RF-input Doherty-like LMBA. Design equations are derived and the fundamental operation is studied. This variant presents several advantages over other known architectures, such as higher gain and device periphery scaling of the different transistors.\ua0The third part proposes a new measurement-based ALM PA design procedure, which emulates the full behavior of the transistors in any ALM architecture using active load-pull measurements. This method can predict the intricate behavior in ALM PAs and it gives measurement-based insights into the internal operation of the circuit already at the design stage. This facilitates the design for optimal ALM PA performance. \ua0The thesis contributes with several promising techniques for reducing performance trade-offs and improving the overall performance of ALM PAs. Therefore, the results will contribute to the development of more energy efficient and high capacity wireless services in the future

Design and analysis of wideband passive microwave devices using planar structures

A selected volume of work consisting of 84 published journal papers is presented to demonstrate the contributions made by the author in the last seven years of his work at the University of Queensland in the area of Microwave Engineering. The over-arching theme in the author’s works included in this volume is the engineering of novel passive microwave devices that are key components in the building of any microwave system. The author’s contribution covers innovative designs, design methods and analyses for the following key devices and associated systems: Wideband antennas and associated systems Band-notched and multiband antennas Directional couplers and associated systems Power dividers and associated systems Microwave filters Phase shifters Much of the motivation for the work arose from the desire to contribute to the engineering o

Passive and active circuits in cmos technology for rf, microwave and millimeter wave applications

The permeation of CMOS technology to radio frequencies and beyond has fuelled an urgent need for a diverse array of passive and active circuits that address the challenges of rapidly emerging wireless applications. While traditional analog based design approaches satisfy some applications, the stringent requirements of newly emerging applications cannot necessarily be addressed by existing design ideas and compel designers to pursue alternatives. One such alternative, an amalgamation of microwave and analog design techniques, is pursued in this work. A number of passive and active circuits have been designed using a combination of microwave and analog design techniques. For passives, the most crucial challenge to their CMOS implementation is identified as their large dimensions that are not compatible with CMOS technology. To address this issue, several design techniques – including multi-layered design and slow wave structures – are proposed and demonstrated through experimental results after being suitably tailored for CMOS technology. A number of novel passive structures - including a compact 10 GHz hairpin resonator, a broadband, low loss 25-35 GHz Lange coupler, a 25-35 GHz thin film microstrip (TFMS) ring hybrid, an array of 0.8 nH and 0.4 nH multi-layered high self resonant frequency (SRF) inductors are proposed, designed and experimentally verified. A number of active circuits are also designed and notable experimental results are presented. These include 3-10 GHz and DC-20 GHz distributed low noise amplifiers (LNA), a dual wideband Low noise amplifier and 15 GHz distributed voltage controlled oscillators (DVCO). Distributed amplifiers are identified as particularly effective in the development of wideband receiver front end sub-systems due to their gain flatness, excellent matching and high linearity. The most important challenge to the implementation of distributed amplifiers in CMOS RFICs is identified as the issue of their miniaturization. This problem is solved by using integrated multi-layered inductors instead of transmission lines to achieve over 90% size compression compared to earlier CMOS implementations. Finally, a dual wideband receiver front end sub-system is designed employing the miniaturized distributed amplifier with resonant loads and integrated with a double balanced Gilbert cell mixer to perform dual band operation. The receiver front end measured results show 15 dB conversion gain, and a 1-dB compression point of -4.1 dBm in the centre of band 1 (from 3.1 to 5.0 GHz) and -5.2 dBm in the centre of band 2 (from 5.8 to 8 GHz) with input return loss less than 10 dB throughout the two bands of operation

Design and characterisation of millimetre wave planar Gunn diodes and integrated circuits

Heterojunction planar Gunn devices were first demonstrated by Khalid et al in 2007. This new design of Gunn device, or transferred electron device, was based on the well-established material system of GaAs as the oscillation media. The design did not only breakthrough the frequency record of GaAs for conventional Gunn devices, but also has several advantages over conventional Gunn devices, such as the possibility of making multiple oscillators on a single chip and compatibility with monolithic integrated circuits. However, these devices faced the challenge of producing high enough RF power for practical applications and circuit technology for integration. This thesis describes systematic work on the design and characterisations of planar Gunn diodes and the associated millimetre-wave circuits for RF signal power enhancement. Focus has been put on improving the design of planar Gunn diodes and developing high performance integrated millimetre-wave circuits for combining multiple Gunn diodes. Improvement of device design has been proved to be one of the key methods to increase the signal power. By introducing additional δ-doping layers, electron concentration in the channel increases and better Gunn domain formation is achieved, therefore higher RF power and frequency are produced. Combining multiple channels in the vertical direction within devices is another effective way to increase the output signal power as well as DC-to-RF conversion efficiency. In addition, an alternative material system, i.e. In0.23Ga0.77As, has also been studied for this purpose. Planar passive components, such as resonators, couplers, low pass filters (LPFs), and power combiners with high performance over 100 GHz have been developed. These components can be smoothly integrated with planar Gunn diodes for compact planar Gunn oscillators, and therefore contribute to RF power enhancement. In addition, several new measurement techniques for characterising oscillators and passive devices have also been developed during this work and will be included in this thesis

Extraordinary acoustic transmission via supercoupling and self-interference cancellation

Supercoupling is a widely researched topic in wave engineering, which has been used to build coupling channels that can, in principle, support total transmission and complete phase uniformity, independent of the length of the channel. This has generally been accomplished by employing dispersion in media that display a near-zero index. In the field of acoustics, prior works have required the presence of periodic embedded resonators, such as membranes or Helmholtz resonators, in order to observe near-zero properties. Here it is shown, theoretically and experimentally, that supercoupling can occur in an acoustic channel without the presence of embedded resonators. A compressibility-near-zero (CNZ) acoustic channel was observed to show remarkable properties analogous to those found in electromagnetics. Furthermore, these principles are employed to develop an acoustic power divider, which takes advantage of the CNZ properties of the channel to also exhibit phase invariance at the output. In the next section, another extraordinary acoustic transmission phenomenon is explored, regarding the potential for sending and receiving from a single acoustic transducer at the same time and at the same frequency. This is made possible through an electrical circuit that is designed to cancel self-interfering signals in acoustic measurement systems. Systems that employ self-interference cancellation (SIC) are often referred to as simultaneous transmit and receive (STAR) or in-band full duplex (IBFD) systems, which have recently enabled sending and receiving of Radio Frequency (RF) signals at the same time and at the same frequency. This has led to commercialization efforts with the promise of doubling the throughput of traditional radio systems including Wi-Fi and 5G cellular communications. Prior to these advances, researchers in vibration control explored self-sensing actuator systems, also referred to as sensoriactuators or sensorless control systems. Inspired by these developments, these approaches are combined and extended to explore STAR functionality in an acoustic measurement system. First, self-interference cancellation (SIC) is applied to time-domain measurements to demonstrate the potential for a practical, single-transducer ultrasonic nondestructive evaluation (NDE) system to measure echo returns while it is actively transmitting at the same frequency. Theoretical models and experimental results are presented and discussed.Electrical and Computer Engineerin