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Active antenna

About: Active antenna is a research topic. Over the lifetime, 2246 publications have been published within this topic receiving 26493 citations.


Papers
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Journal ArticleDOI
TL;DR: Noise analysis of parallel feed structures is presented and a new method is introduced where a "noise-equivalent line length" (NELL) is defined, which unifies the contribution of noise from different array elements and is used in the design of a parallel feed structure and as an active circuit replacement criteria in passive arrays.
Abstract: In this work, noise analysis of parallel feed structures is presented. Signal and noise behavior of the feed structures are signified by the newly introduced concepts of "coherent" and "incoherent" impedance match of power-combining structures. It is also shown that a feed structure can be redesigned for low-noise operation without affecting the radiation characteristics. Optimum design of parallel feed structures for low-noise operation is explained. Also an optimum use of active elements in such structures is investigated to have a low overall noise temperature of the antenna array with minimum number of active elements. In the analysis, a new method is introduced where a "noise-equivalent line length" (NELL) is defined. This definition, which unifies the contribution of noise from different array elements, is used in the design of a parallel feed structure and as an active circuit replacement criteria in passive arrays.

11 citations

Journal ArticleDOI
TL;DR: In this article, a very low cost wireless-over-fibre (WOW) system can be implemented without RF amplification by using lossless matching techniques, which can theoretically improve the link gain by more than 8 dB.
Abstract: This paper demonstrates that very low cost wireless-over-fibre systems can be implemented without RF amplification by using lossless matching techniques. Single stub matching circuits were designed on low loss substrates and integrated with photodiode chips and results show that the link gain can be theoretically improved by more than 8 dB. A 2-port link gain model is developed using Agilent ADS which allows simple wideband modeling of such systems. Finally the system is tested using a ldquoliverdquo access point both with and without matching and results show that a maximum RF range of 4 m can be obtained at 2 Mbps data rate over 317 m of installed MMF with no RF amplification.

11 citations

Patent
12 Apr 1994
TL;DR: In this paper, a T/R module or element (62) formed a part of a subarray used in an active array radar is presented. But, unlike the present paper, this paper does not consider the use of photonic interconnects for communication between levels.
Abstract: of EP0620613An electronic device operating in the microwave frequency range has components disposed in a plurality of planes (44 - 60), wherein the planes (44 - 60) are stacked vertically. The electronic device is a T/R module or element (62) forming a part of a subarray used in an active array radar. The T/R module or element (62) comprises a transmit chip, a receive chip, low noise amplifiers, a phase shifter, an attenuator, switches, DC power supply, interconnects that interconnect the foregoing components and logic circuits to control the foregoing components. The components when stacked in a 3-D package are disposed behind a radiator (44) or antenna, which transmits and receives the microwave signals. Behind the T/R module or element (62) is a manifold which provides input and output to and from the T/R module or element (62). The microwave chips of the T/R module are monolithic microwave integrated circuit chips and control logic, which are disposed in an aluminum nitride substrate and coated with a conformal hermetic coating. The 3-D chip package can optionally include microwave channel (58) cooling by adding additional layers (48). The integrated circuits also employ a flip design for mounting to the wafers. Optional photonic interconnects could be used for communication between levels in the 3-D package and can be used between subarrays as a manifold (Fig. 2).

11 citations

Journal ArticleDOI
TL;DR: In this paper, a printed ultra-wideband (UWB) monopole antenna with both tunable and switchable band-notched characteristics is proposed, where an embedded resonant slot loaded with a varactor and a pin diode controlled by DC signal through one common bias network is employed to tune and switch the notch band.
Abstract: A printed ultra-wideband (UWB) monopole antenna with both tunable and switchable band-notched characteristics is proposed. An embedded resonant slot loaded with a varactor and a pin diode controlled by DC signal through one common bias network is employed to tune and switch the notch band. In the \all-pass" state when the two diodes are partially turned on, the power consumption of this active antenna is only 2.4"W. Measured return loss, radiation pattern, gain and group delay of the introduced antenna are presented in this paper.

11 citations

Proceedings ArticleDOI
11 Jun 2000
TL;DR: In this paper, a prototype X-band active antenna array with adaptive optical processing is presented, referred to as an auto-tuning filter, which is able to extract the strongest principal component in a two-signal space with up to 30 dB enhancement with respect to the other signals.
Abstract: A prototype X-band active antenna array with adaptive optical processing is presented. The optical processor, referred to as an auto-tuning filter, is able to extract the strongest principal component in a two-signal space with up to 30 dB enhancement with respect to the other signals. The processor is compact (8 cm by 4 cm) and scalable to a large number of antenna elements and incident RF waves (sources). Three major components of this system are described in detail: (1) the lens antenna array front end with angle-of-arrival pre-processing; (2) the electrooptic modulation and optical carrier suppression stage; and (3) the smart optical processor (auto-tuning filter).

11 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202148
2020113
2019123
201898
201789
2016102