Topic
Active antenna
About: Active antenna is a research topic. Over the lifetime, 2246 publications have been published within this topic receiving 26493 citations.
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Papers
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TL;DR: A slotted patch antenna, resonating at 2.45 GHz for Industrial Scientific Medical band, having excellent return loss of − 30 dB and radiation efficiency of 100%.
Abstract: In this paper, an active antenna is proposed, where microwave amplifier is directly integrated on passive antenna. The amplifier provides required RF power to the antenna, hence improves the system efficiency. This paper presents a slotted patch antenna, resonating at 2.45 GHz for Industrial Scientific Medical band, having excellent return loss of − 30 dB and radiation efficiency of 100%. The microwave amplifier was designed and optimized on AWR Microwave Office software for 11 dB gain and noise figure less than 2 at the frequency of 2.45 GHz. The proposed amplifier type active antenna was designed using FR4 substrate with substrate height, 1.6 mm and dielectric constant of er = 4.4. In active antenna, amplifier provides extra power to the antenna while electric parameters of active antenna are same, such as return loss is − 21.95 dB at 2.11 GHz and the improved bandwidth of 125 MHz. The passive antenna is designed, analyzed and optimized on IE3D Zeland software version 15.30.
Patent•
15 Feb 2015
TL;DR: In this paper, a T/R assembly control chip was proposed for an active phased-array antenna system, where a clear terminal of a second-stage latch register is controlled according to a system clear signal CLEAR.
Abstract: The invention discloses a T/R assembly control chip and application of the T/R assembly control chip in an active phased-array antenna system. The control chip comprises a power-on protection and system reset circuit, a logic conflict protection circuit and a voltage abnormity and system power down protection circuit, wherein a clear terminal of a second-stage latch register is controlled according to a system clear signal CLEAR, when the system clear signal CLEAR is valid, data in the second-stage latch register are cleared, and a T/R assembly is in a protection state; when a transmitting synchronous signal TR_T and a receiving synchronous signal TR_R are at high levels at the same time, receiving/transmitting buffer drivers are both stopped, and the T/R assembly is in the protection state; when a power supply voltage of the control chip is abnormal, the buffer drivers are controlled to be stopped, and the T/R assembly is in the protection state. The T/R assembly control chip has a power-on protection function, a system reset function, a logic conflict protection function, a voltage abnormity protection function and a system power down protection function, the integrity of an active antenna system is improved, and the life cycle cost of a phased-array system is reduced. The invention further discloses the application of the T/R assembly control chip in the active phased-array antenna system.
01 Jan 2016
TL;DR: In this paper, the effect of nonlinear element in radiation pattern of the antenna is studied and a balanced amplifier structure is used to improve performance of the amplifying antenna, considering nonlinear behavior of the active elements.
Abstract: Amplifying reflectarray antenna can be used to increase the overall gain of the antenna in large distance communication systems. However, amplifying reflectarray antenna may become nonlinear in some incident powers which may lead to performance degradation. In this paper nonlinear behavior of an amplifying reflectarray antenna is studied and a new method is proposed to improve the performance of the antenna. Nonlinear analysis of the active unit cell is performed using harmonic balance method considering nonlinear model of the amplifier. Then, the effect of nonlinear element in radiation pattern of the antenna is studied. Aperture coupled patch structure is used to analyze amplifying unit cell. Finally, an amplifying reflectarray antenna considering nonlinear behavior of the active elements is designed and the proposed balanced amplifier structure is used to improve performance of the amplifying antenna.
Dissertation•
01 May 2007
TL;DR: In this paper, the authors have discussed the integration of active antennas by combining both transmit and receive functions into one single antenna, and the results showed that the active integrated antenna has 3 dB extra gain compared to the passive antenna for both transmission and receive.
Abstract: An active antenna with simultaneous transmit and receive function, integrate an active devices onto a printed antenna to improve its performance or combine functions within the antenna itself. Such antenna are of increasing interest, as system designers require more complex functions to be implemented in reduced space. This paper discusses the integration of active antennas by combining both transmit and receive functions into one single antenna. Four main components in the design are circular polarized microstrip patch antenna, rat race coupler, power divider and amplifiers. All the simulations are done using the Agilent ADS. The circular polarized antenna resonates at 2. 4 GHz. Two MESFET amplifiers have been used to transmit and receive the channel separately. The rat race coupler isolates the two channels and a Tee junction power divider is connected the two channels to the input and output port. The channels are of the same frequency. The simulation and measurement results of the microstrip patch antenna for S11 are lower than -10 dB at frequency of 2.4 GHz. The antenna polarization is confirmed as a circular polarized, as can be seen in the radiation pattern from the measured and simulated results. The amplifier biasing circuit is supplied by two power sources; one is the drain voltage (Vds) which is positive and the other is the gate voltage (Vgs), which is negative. After integrating all of the components, the radiation pattern is measured for both transmit and receive. The beamwidth of the antenna is in the range of 60o – 70o for H plane. The radiation pattern for E plane is smaller compared with the H plane. The comparison between the passive and the active integrated antenna shows that the active integrated antenna has 3 dB extra gain compared to the passive antenna for both transmit and receive. The isolation between transmit and receive is between 20 – 25 dB.
Patent•
28 Aug 2003TL;DR: In this paper, an active antenna system of a radio communication terminal includes: a directional antenna for transmitting and receiving an RF signal to and from a base station through a radio link; and an amplifying unit integrated on one board together with the directional antenna and amplifying and filtering the RF signal.
Abstract: An active antenna system of a radio communication terminal includes: a directional antenna for transmitting and receiving an RF signal to and from a base station through a radio link; and an amplifying unit integrated on one board together with the directional antenna and amplifying and filtering the RF signal. A transmistering the RF signal. A transmistivity of a radio communication terminal is improved, a loss according to a transmission path between an active antenna and the radio communication terminal can be compensated, and a speech quality can be maintained by above a certain level even in an area remote from a base station.