Merv Haynes

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Papers by Merv Haynes

MEMS Switch for Monolithic Implementation in a Miniature Reconfigurable Microwave Filter

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High-Resolution Raman Temperature Measurements in GaAs p-HEMT Multifinger Devices

IEEE Transactions on Electron Devices, 2007

Self-heating in multifinger GaAs pseudomorphic-HEMT devices was investigated by micro-Raman spect... more Self-heating in multifinger GaAs pseudomorphic-HEMT devices was investigated by micro-Raman spectroscopy. The device temperature was probed on the die as a function of applied bias, external heating, and device geometry. The temperature of the top GaAs layer was recorded inside the source-drain gap, as well as on the device periphery using 488-nm laser excitation. Obtained Raman temperatures were found to

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RF-IV waveform engineering inspired MMIC design

The research work presented in this thesis sets out to investigate improvements to the power ampl... more The research work presented in this thesis sets out to investigate improvements to the power amplifier (PA) design cycle through the use of Waveform Engineering techniques. This is approached using alternative simulation methods with strong links to the data available from time domain based radio frequency waveform measurement and characterisation systems. One key objective of this work is to improve the overall efficiency of the radiofrequency power amplifier stage by focusing on circuit design. More specifically, the direct utilisation of waveform-engineering techniques in the development of multi-stage amplifiers to improve power added efficiency was targeted. In developing these power amplifier design methodologies, the techniques are demonstrated and validated using monolithic microwave integrated circuit (MMIC) implementation. This work has also led to an increase in understanding of the operation of the device terminal waveforms which is used to drive an alternative simulatio...

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PAE improvement using 2<sup>nd</sup> harmonic source injection at x-band

2012 Workshop on Integrated Nonlinear Microwave and Millimetre-wave Circuits, 2012

ABSTRACT Theory and measurements are presented comparing Class B amplifier performance of a 0.5 W... more ABSTRACT Theory and measurements are presented comparing Class B amplifier performance of a 0.5 W GaAs pHEMT driven with (a) a sinusoidal signal or (b) using 2nd harmonic input injection. Engineering the input waveform in this way leads to a class B operating mode requiring 3.4 dB less input drive at 9 GHz. This increases power gain and maintains the output power. The 2nd harmonic injection case then shows a 5.9% PAE improvement over the class B case.

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High Efficiency PA Design Strategy at X-Band

2013 IEEE Compound Semiconductor Integrated Circuit Symposium (CSICS), 2013

ABSTRACT There is an growing demand for high efficiency power amplifiers at high frequencies, X-b... more ABSTRACT There is an growing demand for high efficiency power amplifiers at high frequencies, X-band and above. It is well understood that design strategies targeting high efficiency requires output IV waveform engineering; switching the mode of device operation from the Class A or AB modes to the Class B or C modes. Unfortunately, this mode switch results in a significant reduction in gain, which since the maximum amount of gain at high frequencies is limited, can result in degraded rather than enhanced power added efficiency. An improved design strategy, incorporating input IV waveform engineering, can be used to minimize this gain reduction thus providing for improved power added efficiency.

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Wideband monolithic SDLA design using InP DHBT technology

IET Seminar on RF and Microwave IC Design

The design and measurement of a wideband successive detection logarithmic amplifier (SDLA) monoli... more The design and measurement of a wideband successive detection logarithmic amplifier (SDLA) monolithic microwave integrated circuit (MMIC) using InP double heterojunction bipolar transistor technology (DHBT), is described in this paper. The MMIC uses cascaded differential amplifier gain stages together with full wave detectors to achieve a piecewise linear approximation to the ideal logarithmic response. The configuration also includes a limited RF output and on chip adjustment for gain and detector slope. The integrated circuit provides 33 dB dynamic range across 2-18 GHz for a ±1 dB log error, with a limited RF output of >-2.2 dBm. The circuit consumes 690 mW from a single -5 V supply rail in a chip area of 2.58 mm2. (6 pages)

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Merv Haynes

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