Query: High Efﬁciency RF and Microwave Solid State Power Ampliﬁers

Candidate papers:

abstract: Preface. About the Authors. Acknowledgments. 1 Power Amplifier Fundamentals. 1.1 Introduction. 1.2 Definition of Power Amplifier Parameters. 1.3 Distortion Parameters. 1.4 Power Match Condition. 1.5 Class of Operation. 1.6 Overview of Semiconductors for PAs. 1.7 Devices for PA. 1.8 Appendix: Demonstration of Useful Relationships. 1.9 References. 2 Power Amplifier Design. 2.1 Introduction. 2.2 Design Flow. 2.3 Simplified Approaches. 2.4 The Tuned Load Amplifier. 2.5 Sample Design of a Tuned Load PA. 2.6 References. 3 Nonlinear Analysis for Power Amplifiers. 3.1 Introduction. 3.2 Linear vs. Nonlinear Circuits. 3.3 Time Domain Integration. 3.4 Example. 3.5 Solution by Series Expansion. 3.6 The Volterra Series. 3.7 The Fourier Series. 3.8 The Harmonic Balance. 3.9 Envelope Analysis. 3.10 Spectral Balance. 3.11 Large Signal Stability Issue. 3.12 References. 4 Load Pull. 4.1 Introduction. 4.2 Passive Source/Load Pull Measurement Systems. 4.3 Active Source/Load Pull Measurement Systems. 4.4 Measurement Test sets. 4.5 Advanced Load Pull Measurements. 4.6 Source/Load Pull Characterization. 4.7 Determination of Optimum Load Condition. 4.8 Appendix: Construction of Simplified Load Pull Contours through Linear Simulations. 4.9 References. 5 High Efficiency PA Design Theory. 5.1 Introduction. 5.2 Power Balance in a PA. 5.3 Ideal Approaches. 5.4 High Frequency Harmonic Tuning Approaches. 5.5 High Frequency Third Harmonic Tuned (Class F) 5.6 High Frequency Second Harmonic Tuned. 5.7 High Frequency Second and Third Harmonic Tuned. 5.8 Design by Harmonic Tuning. 5.9 Final Remarks. 5.10 References. 6 Switched Amplifiers. 6.1 Introduction. 6.2 The Ideal Class E Amplifier. 6.3 Class E Behavioural Analysis. 6.4 Low Frequency Class E Amplifier Design. 6.5 Class E Amplifier Design with 50# Duty cycle. 6.6 Examples of High Frequency Class E Amplifiers. 6.7 Class E vs. Harmonic Tuned. 6.8 Class E Final Remarks. 6.9 Appendix: Demonstration of Useful Relationships. 6.10 References. 7 High Frequency Class F Power Amplifiers. 7.1 Introduction. 7.2 Class F Description Based on Voltage Wave shaping. 7.3 High Frequency Class F Amplifiers. 7.4 Bias Level Selection. 7.5 Class F Output Matching Network Design. 7.6 Class F Design Examples. 7.7 References. 8 High Frequency Harmonic Tuned Power Amplifiers. 8.1 Introduction. 8.2 Theory of Harmonic Tuned PA Design. 8.3 Input Device Nonlinear Phenomena: Theoretical Analysis. 8.4 Input Device Nonlinear Phenomena: Experimental Results. 8.5 Output Device Nonlinear Phenomena. 8.6 Design of a Second HT Power Amplifier. 8.7 Design of a Second and Third HT Power Amplifier. 8.8 Example of 2nd HT GaN PA. 8.9 Final Remarks. 8.10 References. 9 High Linearity in Efficient Power Amplifiers. 9.1 Introduction. 9.2 Systems Classification. 9.3 Linearity Issue. 9.4 Bias Point Influence on IMD. 9.5 Harmonic Loading Effects on IMD. 9.6 Appendix: Volterra Analysis Example. 9.7 References. 10 Power Combining. 10.1 Introduction. 10.2 Device Scaling Properties. 10.3 Power Budget. 10.4 Power Combiner Classification. 10.5 The T junction Power Divider. 10.6 Wilkinson Combiner. 10.7 The Quadrature (90 Hybrid. 10.8 The 180 Hybrid (Ring Coupler or Rat race) 10.9 Bus bar Combiner. 10.10 Other Planar Combiners. 10.11 Corporate Combiners. 10.12 Resonating Planar Combiners. 10.13 Graceful Degradation. 10.14 Matching Properties of Combined PAs. 10.15 Unbalance Issue in Hybrid Combiners. 10.16 Appendix: Basic Properties of Three port Networks. 10.17 References. 11 The Doherty Power Amplifier. 11.1 Introduction. 11.2 Doherty's Idea. 11.3 The Classical Doherty Configuration. 11.4 The 'AB C' Doherty Amplifier Analysis. 11.5 Power Splitter Sizing. 11.6 Evaluation of the Gain in a Doherty Amplifier. 11.7 Design Example. 11.8 Advanced Solutions. 11.9 References. Index.
author_names: Paolo Colantonio

Franco Giannini

Ernesto Limiti
title: High Efficiency RF and Microwave Solid State Power Amplifiers
year: 2009

abstract: In the last 10 years or so wide bandgap transistors (SiC MESFETs and GaN HEMTs) have appeared on the market for high power RF/microwave transistors. They offer higher power density and higher voltage operation, which in turn are associated with much lower parasitic capacitances and much higher load line dynamic resistance, and hence wider bandwidth applications. Of the two kinds the GaN HEMTs offer higher gain performance and became dominant on the market. The much wider bandwidth matching networks though could not be designed optimally with the traditional Smith Chart and optimization techniques [1] The new requirements for broadband high power and high efficiency performance requires new more sophisticated matching networks synthesis techniques such as the real frequency technique [4] [7]
author_names: Ivan Boshnakov

Anna Wood

Simon Taylor
title: RF and microwave solid state power amplifiers design requires specialised engineering
year: 2012

abstract: Two solid state power amplifiers with record high power added efficiency (PAE) and 100 130 mW output power in 250 nm InP HBT are reported. The 71 95 GHz PA demonstrates 20.7 dB S21 and 25 GHz 3 dB bandwidth at 432.5 mW PDC. Pout is 105 138 mW (21 36% PAE) and RF power density is 1.64 2.15 W/mm. At 81 GHz, 135.6 mW Pout is achieved with 36.0% PAE and 14.1 dB gain. At 81 GHz with reduced input stage bias, 129.6 mW Pout is achieved with 40.0% PAE and 13.0 dB gain. The 96 120 GHz PA demonstrates 17.8 dB S21 and 26 GHz 3 dB bandwidth at 442.4 mW PDC. Pout is 84.9 107 mW and RF power density is 1.33 1.64 W/mm. At 102.5 GHz, 98.1 mW Pout is achieved with 21.2% PAE and 12.1 dB gain. The results were obtained class A DC biasing the PA's. The amplifiers utilizes a novel, compact, and stackable power cell topology for multi finger HBTs operating at mm wave and THz frequencies, where 8 way PA cell combining can be realized for future 0.6 0.8 W Pout designs these designs are currently under development. This work represents record PAE for 100 mW PA's at these frequencies. 40% PAE at E band (81 GHz) is demonstrated for the first time under class A bias, as well as PAE greater than 23% across the 71 76, 81 86, and 92 95 GHz bands. The 18.9 22.5% PAE at 100 mW power for the 96 120 GHz PA is a 1.5 3x improvement to state of the art PAE at these frequencies.
author_names: Zach Griffith

Miguel E Urteaga

Petra Rowell

Richard Pierson
title: 71 95 GHz (23 40% PAE) and 96 120 GHz (19 22% PAE) high efficiency 100 130 mW power amplifiers in InP HBT
venue: 2016 IEEE MTT S International Microwave Symposium (IMS)
year: 2016

abstract: In this paper solid state microwave power amplifiers, which have been developed by GTE Telecomunicazioni for radio link equipments, are described. The main advantages of these "division multiplication" amplifier systems are considered, with reference to both the high overall efficiency and output power. Particular attention is paid to the performance improvements obtained by using broadband thin film frequency multipliers and transistorized microwave dividers.
author_names: A Faotto
title: RF Power Solid State Amplifiers for Microwave Radio
venue: 1976 6th European Microwave Conference
year: 1976

abstract: A novel Ka band high efficiency asymmetric waveguide four port combiner for coherent combining of two Monolithic Microwave Integrated Circuit (MMIC) Solid State Power Amplifiers (SSPAs) having unequal outputs has been successfully designed, fabricated and characterized over the NASA deep space frequency band from 31.8 to 32.3 GHz. The measured combiner efficiency is greater than 90 percent, the return loss greater than 18 dB and input port isolation greater than 22 dB. The manufactured combiner was designed for an input power ratio of 2:1 but can be custom designed for any arbitrary power ratio. Applications considered are NASA s space communications systems needing 6 to 10 W of radio frequency (RF) power. This Technical Memorandum (TM) is an expanded version of the article recently published in Institute of Engineering and Technology (IET) Electronics Letters.
author_names: Edwin G Wintucky

Rainee N Simons

Christine T Chevalier

John Christian Freeman
title: High Efficiency Ka Band Solid State Power Amplifier Waveguide Power Combiner
year: 2010

abstract: Energy efficient conversion of electrical grid power into radio frequency power is becoming one of the key aspects of future accelerators. A significant part of the initial investment and running costs of these machines will be determined by the cost and efficiency of their RF systems. For largescale accelerators, which are proposed for instance by the International Linear Collider Study or by the Future Circular Collider Study, RF efficiency will likely be a determining factor in the approval process. Efforts are already in place to stretch the efficiency of existing RF sources to higher levels. Well known technologies such as klystrons are being reinvented with modern day beam physics, inductive output tubes are being combined for higher power output, and modular solid state amplifiers are becoming more popular as RF sources for accelerators. This talk will give an overview of recent advances and trends in RF source developments. It will discuss future needs and the strategy towards higher efficiency devices for the benefit of the accelerator community. THE NEED FOR HIGHER EFFICIENCY RF SOURCES The electrical power consumption of future accelerators will be driven to a large part by their RF systems. This is particularly true for electron colliders, circular (e.g. FCC) or linear (e.g. ILC or CLIC) which need RF systems in the order of 100 MW or above (see Table 1, [1 6] Other examples with significant RF power consumption are high power hadron linacs (e.g. ESS) and cyclotrons (PSI) for neutron science or Accelerator Driven Systems. In the case of hadron colliders, magnet systems dominate electrical power consumption while RF systems only use a few percent. At CERN, where most accelerators are circular, only 6% of the annual consumption 1.1 TWh in 2017) are caused by the RF systems. For a 3 TeV CLIC machine, around 50% of the facility power consumption is due to the RF system. With an estimated yearly total of 2.74 TWh [4] and a European average price for non household consumption of 0.1e/kWh in 2017, this translates into 187 Me of electricity costs/year for the RF system alone. Therefore every percentage point in RF efficiency has a significant impact on the running cost. For Accelerator Driven Systems (ADS) the power to run the accelerator complex (including cooling, ventilation, cryogenics, offices, etc. must be small (5 10% compared to the power, which is produced in the ADS core. To achieve these values the accelerator complex must have a total efficiency between 0.2 eacc 0.4 [7] which presents a challenge for today's accelerators. If not achieved, the idea frank.gerigk@cern.ch Table 1: RF Power for Various Future Accelerators Project Ptotal [MW] PRF [MW] Pbeam [MW] PSI* 10 4 1.3 LEP2+ 120 42 19 FCC ee+ tbd 165 100 ESS* 35 15 5 CLIC 500* 272 109 9.8 ILC 500* 164 68 9.4 CLIC 3000* 582 289 28 total power is for the whole facility with experiments, +without injector of using ADS for energy production is unlikely to become economically viable [8] TODAY'S TECHNOLOGIES NEW DEVELOPMENTS In the following we will review today's state of the art of high power RF sources (see Table 2) and point to developments, which may change their efficiencies or power reach in the near future. As pulsed and Continuous Wave (CW) operation pose different challenges to the RF sources both modes of operation will be treated. Modulator Efficiency Most high power RF sources need a High voltage (HV) modulator, which transforms the voltage of the electrical grid to the HV and pulse pattern needed by the RF source. For CW operation in general but also for pulsed operation of gridded tubes (tetrodes, IOTs) the modulator is basically a HV power supply. Pulsed power for gridded tubes is obtained by simply pulsing the grid using the input RF signal, whereas HV pulses for the operation of non gridded tubes (klystrons, magnetrons) have to be formed by the modulator itself. Various topologies have been developed in recent years, which are adapted to different pulse lengths and voltage needs [9] i) Traditional pulse transformer based modulators with efficiencies between 85% and 90% and rise times in the range of a few hundred microseconds. ii) High frequency transformer based modulators such as the resonant polyphase design employed at SNS [10] or the stacked multi level (SML) design developed and used by the European Spallation Source (ESS) with efficiencies up to 92% and with a very short rise time in the range of 100 ms. iii) Transformerless modulators such as the Marx generator [11] which have the potential for even higher efficiency, or direct switch designs. 9th International Particle Accelerator Conference IPAC2018, Vancouver, BC, Canada JACoW Publishing ISBN: 978 3 95450 184 7 doi:10.18429/JACoW IPAC2018 MOYGB1
author_names: Frank Gerigk
title: Status and Future Strategy for Advanced High Power Microwave Sources for Accelerators
year: 2018

abstract: NASA is planning a number of Space Exploration, Earth Observation and Space Science missions where Ka band solid state power amplifiers (SSPAs) could have a role. Monolithic microwave integrated circuit (MMIC) based SSPAs with output powers on the order of 10 W at Ka band frequencies would be adequate to satisfy the data transmission rate requirements at the distances involved. MMICs are a type of integrated circuit fabricated on a GaAs wafer, which operates at micro wave frequencies and performs the function of signal amplification. The highest power Ka band (31.8 to 32.3 GHz) SSPA to have flown in space had an output power of 2.6 W with an overall efficiency of 14.3 percent. This SSPA was built around discrete GaAs pHEMT (high electron mobility transistor) devices and flew aboard the Deep Space One spacecraft. State of the art GaAs pHEMT based MMIC power amplifiers (PAs) can deliver RF power at Ka band frequencies anywhere from 3 W with a power added efficiency (PAE) of 32 percent to 6 W with a PAE of 26 percent. However, to achieve power levels higher than 6 W, the output of several MMIC PAs would need to be combined using a high efficiency power combiner. Conventional binary waveguide power combiners, based on short slot and magic T circuits, require MMIC PAs with identical amplitude and phase characteristics for high combining efficiency. However, due to manufacturing process variations, the output powers of the MMIC PAs tend to be unequal, and hence the need to develop unequal power combiners. A two way asymmetric magic T based power combiner for MMIC power amplifiers, which can take in unequal inputs, has been successfully designed, fabricated, and characterized over NASA s Deep Space Network (DSN) frequency range of 31.8 to 32.3 GHz. The figure is a transparent view of the a sym metric combiner that shows the 4 port configuration and the internal structure. The rod, post, and iris are positioned by design to achieve the desired asymmetric power ratio, phase equality, and port isolation. Although the combiner was designed for an input power ratio of 2:1, it can be custom designed for any arbitrary power ratio and frequency range. The manufactured prototype combiner was precision machined from aluminum and is less than 2 in.3 (32.8 cm3) Previously investigated rectangular waveguide unequal power combiners were based on shunt/series coupling slots, E plane septums, or H plane T junctions. All the prior art unequal power combiners operated at or below X band (10 GHz) frequencies and were primarily used in the feed network of antenna arrays. The only reported asymmetric magic T was developed as a 2:1 power divider for operation at a much lower frequency, around 500 MHz. The measured power ratio when tested as a power divider was very close to 2 and the phase balance was within 2.6, resulting in near ideal performance. When tested as a combiner using two MMIC SSPAs with a 2:1 power output ratio, an efficiency greater than 90 percent was demonstrated over the 500 MHz DSN frequency range. The return loss at the combiner output port (1) was greater than 18 dB and the input port (2 and 3) isolation was greater than 22 dB. The results show the asymmetric combiner to be a good candidate for high efficiency power combining of two or more SSPAs needed to achieve the 6 to 10 W required by space communications systems of future NASA missions.
author_names: Edwin G Wintucky

Rainee N Simons

John Christian Freeman

Christine T Chevalier
title: High Efficiency Ka Band Waveguide Two Way Asymmetric Power Combiner
year: 2011

abstract: The two basic types of RF power amplifiers are TWT amplifiers (TWTAs) and solid state power amplifiers (SSPAs) At the lower frequency bands, for example UHF (300 MHz to 3 GHz) SSPAs predominate while TWTAs are typically used at higher microwave frequencies. As discussed in Chapter 1, the basic building block of an SSPA is a power transistor. A single transistor can act as an amplifier, but to meet a certain gain or power output requirement, several stages containing one or more transistors are usually cascaded together. For example, Figure 3.1 shows a three stage power amplifier; the first or input stage has high gain and low output power since the signal level is low, while the final or output stage typically has low gain but high output power. Output stages often use two or more devices in parallel to increase the available output power. The purpose of the second or driver stage is to provide sufficient input power to the output stage; if the driver is not powerful enough, then the potential high power output will never actually be achieved. Chapter 5 shows several practical examples of different amplifier line ups. One of the many important parameters of an amplifier is its power conversion efficiency (symbol e, units Power conversion efficiency is a measure of how effectively an amplifier converts power drawn from the dc supply to useful signal (RF) power delivered to a load, that is, 79
title: Power Amplifiers and System Design 3.1 Amplifier Efficiency

abstract: Power amplification at microwave frequency and above is one of strategic targets under investigation of vacuum microelectronic devices, because it has possibilities to generate more output power and higher frequency than solid state devices. Most of this work has focussed on a triode structure commonly based on a field emission array (FEA)l) FEA is sufficiently nonlinear in I V characteristics associated with Fowler Nordheim equation, which provides highly efficient operation, as expected from B and C class amplifiers. This is an additional advantage in EA based devices. FEA driven by RF power emits a pulsed electron beam with narrow width repeated at the RF signal. When the beam is sufficiently accelerated and coupled with a RF circuit, one can create a high power and high efficiency amplifier having a simple structure without the velocity modulation required in a multicavity klystron. Additionally, highly efficient harmonic amplification up to a higher order becomes possible by coupling with a harmonic RF circuit2) The paper describes the expected operation for the tubes. Figure 1 shows a schematic drawing of the microwave amplifier or frequency multiplier using the FEA. Figure 2 shows a phase distribution of emitted electron current density calculated for a RF FEA with tip density of 1.6x107A/cm2 by using the WKB approximation under a suitable tip shape. The emitted electrons are well bunched within a narrow range of RF phase, as shown in Fig. 2. Table 1 shows the peak efficiencies and output powers for the fundamental and higher harmonic operations. Here, the cathode diameter of lmm and an accelerating voltage of 30kV are assumed. Extraordinarily high efficiencies of 97% 90% 78% and 50% are expected at the fundamental, second, third and even fifth harmonics, respectively, and several tenth kW of output power are extracted from the simple and light weight tube. Operation frequency is commonly limited by the cut off frequency governed by transconductance and the parasitic capacitance of the FEA. However, there are many method to overcome the frequency limitation. For examples, since FEA is installed in a reentrant cavity at high frequency operation, a field emission may be extracted by RF field added on DC bias or basically no extraction electrode may be required for RF FEA operation. Furthermore, distributed interaction structure and Bragg resonator structure with or without gate electrode may be considered at millimeter waves and optical waves3)
author_names: Kuniyoshi Yokoo

Hidetaka Shimawaki

Shoichi Ono
title: Proposal Of A High Efficiency Microwave Power Source Using A Field Emission Array
venue: [Proceedings] IVMC '93 Sixth International Vacuum Microelectronics Conference
year: 1993

abstract: Modern communication satellites carrying large numbers of signals require High PoWer Amplifiers (HPAs) which provide RF power with high linearity and high efficiency. Solid state power amplifiers (SSPAs) and travelling wave tube amplifiers (TWTAs) are the candidates for thiS application. Predistortidn linearizer circuits, are used to improve the performance of these aimplifier types. A 10.7 to 12.75 GHz predistortion linearizer is realized in coplanar waveguide tchnology with only three active elements, two Schottky diodes and one monolilthic microwave integrated circuit (MMIC) amplifier. This linearizer shows good capabilities for gain and phase adjustments: gain expansion of 5 dB and phase shift between 20 and 50 degrees can be obtained with this circuit over 2 GHz of bandwidth and about 10 12 dB input power dynamic range. Furtheron, the linearizer offers an input and output VSWR of better 1.4 1 over bandwidth. Low mass and size and increased reliability makes this linearizer suitable for satellite as well as for ground station applications.
author_names: Gerhard Eggers

Rudolf Kohl
title: 2 GHz Bandwidth Predistortion Linearizer for Microwave Power Amplifiers at Ku Band
venue: 1994 24th European Microwave Conference
year: 1994