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Session: WE4E3:30 PM Wednesday, May 26, 2010 Room: 207D |
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Session: WE4E | Power-Amplifier and Combiner Techniques for HF, VHF, and UHF |
Chair: | Richard Campbell, Portland State University |
Co-Chair: | Robert Caverly, Villanova University |
Abstract: | This session features the latest developments in technology for power amplifiers and combiners operating at HF, VHF, and UHF. Included are techniques for increasing efficiency by using radio-frequency pulse-width modulation and envelope tracking. Also included are a broadband power amplifier based upon GaN FETs and an integrated-circuit class-F amplifier. Complementing the amplifiers is a technique for reconfiguring a radial combiner to operate at different frequencies. |
| | WE4E-1 | Class-D Power Amplifier with RF Pulse-Width Modulation | 3:30 PM-3:50 PM | F. H. Raab, Green Mountain Radio Research Company, Colchester, United States |
(1004) | Single-ended (monopolar) and push-pull (bipolar) power amplifiers (PAs) are based upon complementary class-D PAs. The radio-frequency pulse-width modulation (RFPWM) waveform is produced in software and downloaded to a programmable-waveform generator. The PAs operate at 500 kHz and produce peak outputs of 100 W (monopolar) and 187 W (bipolar) with 85-percent efficiency. These amplifiers exhibit excellent linearity; IM products for single-tone AM and two-tone signals are about 40 dB below the desired sidebands. High efficiency is maintained over a dynamic range of 13 to 15 dB. This results in average efficiencies of 84 percent for signals with peak-to-average ratios up to 6 dB and 80 percent for a peak-to-average ratio of 10 dB. RFPWM also produces a clean output spectrum in which the spurious products are well removed from the desired signal. | | |
WE4E-2 | An Efficient, 35 dBm, Inverse Class-F, UHF RF Power Amplifier Module on a 12 mm2 Footprint Designed in First Pass through Accurate Modeling and Simulation | 3:50 PM-4:10 PM | M. J. Franco, RFMD, Greensboro, United States |
(1284) | This paper describes the design, simulation and experimental verification of an efficient, 35 dBm, RF power amplifier (PA) module, implemented in gallium arsenide heterojunction bipolar transistor semiconductor technology (GaAs HBT). The PA module, which includes all the power supply decoupling and matching components, occupies an area of only 12 mm2 and achieves outstanding output power flatness (±0.125 dB) from 824 to 915 MHz and a power added efficiency (PAE) of 60%. The simulation methodology developed allowed for the accurate prediction and optimization of performance entirely through simulation, enabling first pass success both in die and laminate fabrication. The amplifier did not require any tuning or component adjustment to achieve full performance after automated fabrication, resulting in a significant decrease in development time. | | |
WE4E-3 | Switch-Controlled Multi-Octave Bandwidth Radial Power Divider/Combiner | 4:10 PM-4:30 PM | Y. Hong1, D. F. Kimball2, J. Yook1, P. M. Asbeck2, L. E. Larson2, 1Yonsei University, Seoul, Republic of Korea, 2University of California, San Diego, La Jolla, United States |
(1366) | An improved very wideband radial waveguide-based power divider/combiner is presented, which uses switching to compensate for cavity resonance. The combiner is implemented with broadband probes composed of cylindrical conductors and dielectric spacers, arranged on a rod for mechanical stability. The proposed switch-controlled radial power combiner provides low loss ( 1 dB), broad bandwidth (400 MHz~2000 MHz), and high power capability. | | |
WE4E-4 | High-Efficiency 400 W Power Amplifier with Dynamic Drain Voltage Control for 6 MHz OFDM Signal | 4:30 PM-4:50 PM | S. Hiura, H. Sumi, H. Takahashi, Toshiba Corporation, Corporate Manufacturing Engineering Center, Yokohama, Japan |
(1445) | In this paper, we present a high-efficiency 400 W PA for a 6 MHz OFDM signal with a 10 dB peak-to-average power ratio (PAPR). To improve the efficiency of the PA at a 10 dB backoff from its saturated output power (PSAT), a dynamic drain voltage control is applied, which supplies two different drain voltages depending on the envelope of the OFDM signal. The PA is fabricated using a 400 W push-pull LDMOS FET for an UHF band. The drain current of a single LDMOS FET is 9.5 A at PSAT. The drain voltages used in the control are set to 40 V and 20 V. Measurement results indicate a power-added efficiency (PAE) in the case of dynamic drain voltage control of 34%, which is 15% higher than PAE at a drain voltage of 40 V. This is the highest output power of a PA with a dynamic drain voltage control to the best of our knowledge. | | |
WE4E-5 | 100 W GaN HEMT Power Amplifier Module with 60% Efficiency over 100-1000 MHz Bandwidth | 4:50 PM-5:10 PM | K. Krishnamurthy, T. Driver, R. Vetury, J. Martin, RF Micro Devices, Charlotte, United States |
(1741) | We have demonstrated a decade bandwidth 100 W GaN HEMT power amplifier module with 15.5-18.6 dB gain, 104-121 W CW output power and 61.4-76.6 % drain efficiency over the 100-1000 MHz band. The 2 x 2 inch compact power amplifier module combines four 30 W lossy matched broadband GaN HEMT PAs packaged in a ceramic SO8 package. Each of the 4 devices is fully matched to 50 Ohms and obtains 30.8-35.7 W with 68.6-79.6 % drain efficiency over the band. The packaged amplifiers contain a GaN on SiC device operating at 48V drain voltage, alongside GaAs integrated passive matching circuitry. The four devices are combined using a broadband low loss coaxial balun. We believe this combination of output power, bandwidth and efficiency is the best reported to date. These amplifiers are targeted for use in multi-band public mobile radios and for instrumentation applications. | | |
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