Results 221 to 230 of about 16,196 (251)

Electrically Small Antennas with Miniaturized Impedance Matching Circuits for Semiconductor Amplifiers

IEICE Transactions on Electronics, 2005
In order to reduce the size of a wireless system, we propose a design theory for the broadband impedance matching circuit which connects an electrically small antenna (ESA) to a semiconductor amplifier. We confirmed its validity for the case of connection between a small slot loop antenna with a small radiation resistance of R a = 0.776 Ω and a ...
Keiji Yoshida, Yukako Tsutsumi, Haruichi Kanaya   +2 more
openaire   +1 more source

Mechanical and electrical impedance matching in a piezoelectric beam for Energy Harvesting

The European Physical Journal Special Topics, 2015
A piezoelectric beam is one of transducers for energy harvesting. It provides easy implementation and good performance in changing mechanical stress into electric voltage. In order to maximize output power, it is important to provide mechanical and electrical impedance matching.
A. Koszewnik, P. Grześ, W. Walendziuk
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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   +1 more source

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
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

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

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

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.
openaire   +1 more source