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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)
Fig. 5. Input impedance of the wideband patch antenna with capacitive probe feed. benefits of the subdomain attachment mode over the entire-domain attachment mode is that it can be used with any shape of patch and that it is faster to evaluate. The entire-domain attachment mode has to be derived from scratch for other shapes of patches. One uncertainty(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 pro-grammable gate array (FPGA). The fundamental gain-bandwidth limitations of electrically small antennas(More)
i ABSTRACT An investigation of phase noise in amplifier and voltage-controller oscillator (VCO) circuits was conducted to show that active direct-current (DC) bias techniques exhibit lower phase noise performance than traditional resistive DC bias techniques. Low-frequency high-gain amplifiers like those found in audio applications exhibit much better 1/f(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)
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)
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