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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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Proceedings ArticleDOI
Xiaoyu Cheng1, Jun Shi1, Jungkwun Kim1, Cheolbok Kim1, E. David1, Yong-Kyu Yoon1 
20 Jun 2011
TL;DR: In this paper, an omni-directional patch antenna is integrated with an active low noise amplifier in the cavity formed by the folded patch, demonstrating an improved gain and sensitivity, which is attributed to the power gain of the integrated amplifier.
Abstract: Recently, an omni-directional patch antenna has been demonstrated by folding the patch in a rectangular wave guide shape, and therefore the inside of the folded patch secures a good electromagnetic shielding zone. However, because of the folding architecture, the antenna gain (for transmitting) and sensitivity (for receiving) has been greatly reduced. In this work, the patch antenna is integrated with an active low noise amplifier in the cavity formed by the folded patch, demonstrating an improved gain and sensitivity, which is attributed to the power gain of the integrated amplifier. Since the amplifier has been self-packaged in the cavity shielded by the ground plane of the patch antenna, it does not interfere with the antenna radiation and any other external circuitry. It preserves its omni-directional radiation characteristic, which finds great usage for many biomedical applications and sensor systems such as a biomedical wireless endoscope. Also, since it is folded, its footprint has been reduced compared to its planar counterpart. In addition, the gap between the edges of the folded patch is utilized for impedance matching, not requiring an additional impedance matching circuit between the antenna and the feeding circuit. Integrated with a low noise amplifier circuit consisting of NBB-400 (RFMD, Inc.) and some passives in the cavity area, a self-packaged omnidirectional active antenna operating at 2.4 GHz with a dimension of 19mm × 18.4mm × 18.4mm (length × width × height) is successfully demonstrated. The footprint has been reduced by more than 50% compared with its counterpart. The structure has been simulated using a high frequency structure simulator (HFSS, Ansys Inc.) and the results show good agreement with measurement results.

3 citations

Proceedings ArticleDOI
01 Oct 1995
TL;DR: In this article, the authors describe the design and construction of uniplanar GaAs HEMT oscillator which couples the electromagnetic energy to the microstrip leaky-wave antenna on the same substrate.
Abstract: In this paper we describe the design and construction of uniplanar GaAs HEMT oscillator which couples the electromagnetic energy to the microstrip leaky-wave antenna on the same substrate. The microstrip line was excited by a slotline on the opposite side of the substrate to obtain the desired first higher-order odd mode excitation. Thereby, the directional RF beam can be combined quasi-optically through the active antenna array. The active antennas were built in the form of uniplanar MICs (microwave integrated circuit), where no via holes and no DC blocking capacitance are required. The prototype active antenna was designed and tested at X-band, but it can be extended to higher frequency for quasi-optical application.

3 citations

Patent
28 Jan 2015
TL;DR: In this article, a TDD-LTE multiple-input-multiple-output (MIMO) indoor coverage system using a directional coupler with high directivity and uplink signal amplitude limiting processing to solve the problem of uplink interference of a traditional envelope detection level trigger scheme is presented.
Abstract: The invention provides a TDD-LTE multiple-input-multiple-output indoor coverage system. The system comprises an active near-end machine directly coupled with an RRU (Remote Radio Unit) antenna port and a far-end active antenna, wherein the active near-end machine and the far-end active antenna are connected through an indoor signal distribution system. The TDD-LTE multiple-input-multiple-output indoor coverage system uses a directional coupler with high directivity and uplink signal amplitude limiting processing to solve the problem of uplink interference of a traditional envelope detection level trigger scheme. The system further uses a scheme of uplink and downlink frequency converter sharing so as to simplify circuit design, substantially reduce the equipment cost and improve the product cost performance under the condition of no sacrificing of system performance.

3 citations

Patent
01 Jun 1998
TL;DR: In this paper, a method and system of merging signals feeding the antenna elements by using a combiner network and to create an antenna reference point representing the signal representation in the air is presented.
Abstract: A method and system of merging signals feeding the antenna elements by using a combiner network and to create an antenna reference point representing the signal representation in the air. This merged signal will be easily accessed for measurement purposes. An additional signal combiner connected to the output terminals of the distributed power amplifier modules of the active antenna creates a measured virtual antenna reference point which may be utilized in testing and typing active antennas having distributed electronics for a certification according to standards for GSM, PDC and DCS. The corresponding method for measuring active receive antennas is also disclosed. Also discloses a measurement system for application of the new method of obtaining a virtual transmit or receive antenna.

3 citations

Proceedings ArticleDOI
01 Jan 2017
TL;DR: The results show that this integrated optical wireless link is very robust for carrying OFDM based wireless LAN signals and helps increasing the coverage service for more than 30 meters when an SMF of 80 km length is used.
Abstract: In this paper, we present an optical OFDM based wireless LAN. The baseband OFDM transmitted signal is fully carried over a radio frequency signal. The directly modulated laser (DML) is used in the system as an optical laser source. Identical photonic antennas are used at the transmitter and the receiver. The simulations were carried out for different SMF and MMF lengths, and the wireless distance between the transmitting and receiving antennas is in a range of 40 dB up to 80 dB. Furthermore, the system performance results are obtained regarding EIPR, SNR, and BER. The results show that this integrated optical wireless link is very robust for carrying OFDM based wireless LAN signals. Moreover, using an active antenna in the system helps increasing the coverage service for more than 30 meters when an SMF of 80 km length is used.

3 citations


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