James T. Aberle

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Adaptive antenna-tuning units (AATUs) provide broadband dynamic tuning to widely-varying antenna impedances caused by the changes in operating frequencies and unpredictable environmental factors. AATUs are becoming a critical need in multimode transceivers, since they minimize the power reflection due to the impedance mismatch between PA/LNA and antenna at(More)
This paper discusses the implementation of an automatic antenna tuning unit system (ATU) for software-defined and cognitive radio. The ATU simplifies radio frequency (RF) front-end design for multi-band, multi-mode radios by allowing an electrically small reconfigurable antenna to become a frequency-agile selective component (essentially a tunable filter).(More)
This paper proposes a novel RF front-end architecture for software-defined radios (SDRs) based on an electronically tunable antenna pair controlled by an antenna control unit (ACU) consisting of field effect transistor (FET) switches and a field programmable gate array (FPGA). The fundamental gain-bandwidth limitations of electrically small antennas prevent(More)
i ABSTRACT A dual-channel directional digital hearing aid (DHA) front end using Micro Electro Mechanical System (MEMS) microphones and an adaptive-power analog processing signal chain is presented. The analog front end consists of a double differential amplifier (DDA) based capacitance to voltage conversion circuit, 40dB variable gain amplifier (VGA) and a(More)
This paper presents modeling of annular patch antenna. The S and Z parameters of an Annular<lb>patch Microstrip antenna are investigated and optimization. The optimization is performed by<lb>varying the inner and outer radius of annular Ring. The impedance and radiation characteristics<lb>of annular patch antenna are examined and compared. It is able to(More)
ii ABSTRACT A dual-channel directional digital hearing aid (DHA) front-end using a fully differential difference amplifier (FDDA) based Microphone interface circuit (MIC) for a capacitive Micro Electro Mechanical Systems (MEMS) microphones and an adaptive-power analog font end (AFE) is presented. The Microphone interface circuit based on FDDA converts the(More)
In this paper, the execution of rectangular patch antenna is mended applying a newly cylindrical electromagnetic band-gap (EBG) substrate. The microstrip patch antenna is fed by the driven terminal. This EBG structure, when comprised with microstrip patch antenna to radiation pattern and return loss got from menstruation appearance a better impedance(More)