Results 221 to 230 of about 17,521 (253)

Stability of non-Foster circuits for broadband impedance matching of electrically small antennas

2015 IEEE Radio and Wireless Symposium (RWS), 2015
Non-Foster circuits are promising for numerous microwave and antenna applications because they are not limited by the gain-bandwidth product. However, the stability of these circuits is a key issue for their design. In this paper we introduce a three-step scheme to systematically stabilize a non-Foster circuit (NFC) topology that can be used in ...
Aseim M. Elfrgani, Roberto G. Rojas
openaire   +2 more sources

Electrical Impedance Matching of PVDF Ultrasonic Transducers

2004
One of the objectives of this work is to improve PVDF ultrasonic transducers characteristics by electrical means. It is feasible to enhance the frequency bandshape and the overall power transfer efficiency in high-Q acousto-electric resonators by balancing the source impedance with the transducer electrical impedance using some form of lumped component
openaire   +1 more source

Wideband, Non-Foster Impedance Matching of Electrically Small Transmitting Antennas

IEEE Transactions on Antennas and Propagation, 2018
Electrically small antennas (ESAs) can be passively matched only over very narrow bandwidths and the resulting antennas have low gains. These are the major limiting factors for ESAs used in transmit applications, especially at high-frequency (HF) and lower Very HF frequency bands.
Ting-Yen Shih, Nader Behdad
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Design of a non-Foster impedance matching network for electrically small antennas

2013 13th Mediterranean Microwave Symposium (MMS), 2013
As an antenna becomes smaller, its input reactance increases to greater than its input resistance, resulting in a significant increase of it radiation quality factor and drastic decrease of its bandwidth. Therefore, there is a need for a matching network at the antenna terminals, which may be devised by negative impedance converters (NIC).
Homayoon Oraizi, Seyyed Hamzeh Hashemi
openaire   +1 more source

Wireless Excitation and Electrical Impedance Matching of Piezoelectric Wafer Active Sensors

Volume 2: Mechanics and Behavior of Active Materials; Integrated System Design and Implementation; Bio-Inspired Materials and Systems; Energy Harvesting, 2012
Wireless ultrasound inspections using Piezoelectric Wafer Active Sensors (PWAS) are attractive for Structural Health Monitoring (SHM). However, the impedance mismatch between the PWAS and the wireless transponder reduces the wirelessly transmitted signal strength.
Rashed Hossain Bhuiyan, MD Mazharul Islam, Haiying Huang   +2 more
openaire   +1 more source

A discussion on the quality factor of impedance matched electrically small wire antennas

IEEE Transactions on Antennas and Propagation, 2005
The quality factors of several impedance matched, electrically small wire antennas are compared as a function of matching technique and antenna geometry. The antennas considered have the same height and wire diameter, and they are designed to be self-resonant at approximately the same frequency.
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Impedance Matching and Electric Field Penetration in Metal Vapour Lasers

1996
In metal vapour lasers (MVL), the lasing atoms are excited by collision with free electrons. The electrons gain their energy from the electric field (EF) within the plasma. High electron energy (in copper vapour laser, about 10 e V) is required in order to create maximal population inversion.
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Non-Foster impedance matching of an electrically small loop antenna for biomedical telemetry

2017 IEEE Asia Pacific Microwave Conference (APMC), 2017
The demand for miniaturized antennas in biomedical telemetry has been steadily increasing. In biomedical telemetry, electrically small antennas are integrated into exterior portable devices owing to their size in respect of the wavelength to process the received sensing information and power battery-less implantable medical devices (IMDs).
Mohamed Manoufali, Amin Abbosh
openaire   +1 more source

Study of power efficiency of non-foster impedance matching for electrically small antenna

2014 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), 2014
Electrically small antenna has attracted much attention because of its potential application in compact wireless communication and sensing systems. Matching is needed before any practical application for an electrically small antenna (ka < 1, k — wavelength number, a — radius of the smallest sphere that can surround the antenna) because it has an input
Xiaoju Yu, Qi Tang, Min Liang, Hao Xin
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Wideband matching of an electrically small antenna using a negative impedance converter technique

Proceedings of the 2012 IEEE International Symposium on Antennas and Propagation, 2012
This paper presents an analysis and design of a negative impedance converter (NIC) circuit for wideband matching of an electrically small antenna operating in the receive mode, and that stability work condition is also given. Experimental results presented demonstrate that the active receiving antenna exhibits good voltage gain and signal-to-noise ...
WenXing Li, RuiLong Chen, Ning Zhai, Si Li, Raj Mittra   +4 more
openaire   +1 more source