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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TL;DR: In this paper, an interaction of direct-modulated and gain-switched optical links with active antenna phased array systems is demonstrated, where the RF signal directly modulates the DFB laser.
Abstract: With the advance of high speed laser technology, optical interaction with microwave circuits has become highly viable. Such interaction is advantageous as the fiber is low-loss, lightweight, and immune to electromagnetic interference. In this paper, interaction of direct-modulated and gain-switched optical links with active antenna phased array systems is demonstrated. In the direct-modulated optical system, the RF signal directly modulates the DFB laser. In the gain-switched optical system, the laser is gain-switched to function as a RF frequency doubler. The modulated signal is transmitted via an optical fiber and recovered at the receiving end by a high-speed photodetector. The recovered RF is then injected into the active antenna phased array systems as an injection-locking reference signal. Two active antenna systems are used for this demonstration: beam-switching and Doppler transceiver.
6 citations
Proceedings Article•
19 Dec 2013
TL;DR: In this article, the product capabilities and design options that result in improved antenna operating bandwidth are discussed, as well as how to implement aperture tuning and tunable matching networks in 3G/4G/LTE networks.
Abstract: Increased spectrum coverage and data rates required by 3G/4G/LTE mobile wireless devices are dictating the need for active antenna systems. Advancements in technology and design techniques have enabled new and innovative solutions for implementing antenna tuning and impedance matching. High Quality (Q) factor Digitally Tunable Capacitors (DTCs), tuning switches and reconfigurable tuners allow for dynamic adjustment of an antenna's electrical characteristics, and extended low-band coverage through the implementation of aperture tuning and tunable matching networks. This paper discusses the product capabilities and design options that result in improved antenna operating bandwidth.
6 citations
TL;DR: In this paper, a slot-coupled patch antenna with a MESFET oscillator at free-running and injection-locked states is presented, and both radiating and scattering analyses are performed in a unified approach for the transmission-and reflection-type operation modes of ILAA.
Abstract: In this paper, radiating and scattering analyses of a slot-coupled patch antenna loaded with a MESFET oscillator at free-running and injection-locked states are presented. This arrangement is a basic module of an injection-locked active array. With a small injection signal applied directly to the oscillator in a transmission-type mode or indirectly through a patch antenna to the oscillator in a reflection-type mode, the oscillator loaded antenna then becomes an injection-locked active antenna (ILAA) within the locking range. Simulation results yield the oscillating frequency and radiating power at the free-running state and the locking range and radiating power at the injection-locked state. Both radiating and scattering analyses are performed in a unified approach for the transmission-type and reflection-type operation modes of ILAA. Experiments show the validity of the developed theoretical analyses. These results can be applied in the ILAA array design. >
6 citations
TL;DR: In this article, a simple solution for jamming mitigation of L1 band GPS by electronically switching antenna beam for wide and narrow beamwidths is proposed, assuming the jamming signal is directed from low elevation angles, antenna reception can be made significantly lower at these angles by electronically reconfiguring the antenna beamwidth.
Abstract: We propose a simple solution for jamming mitigation of L1 band GPS by electronically switching antenna beam for wide and narrow beamwidths. Assuming the jamming signal is directed from low elevation angles, antenna reception can be made significantly lower at these angles by electronically reconfiguring the antenna beamwidth. Four-element antenna array and one of the elements of the array are designated as antijam (array) mode and normal mode of the antenna. The antenna is placed on a degenerate-ground with symmetric slots in the ground. Front-end configuration for this antenna is also discussed. Simulations and measurements are performed to validate the proposed design. The antenna achieves more than 15 dB rejection in measurements and more than 20 dB cross-polarization improvement compared to standalone (normal mode) antenna. The system can easily be replaced with existing active antenna to improve antijam capability of the receiver.
6 citations
01 Jun 2006
TL;DR: In this paper, the main application is the remote synchronization and control in Ku-band of the elements of an onboard active antenna, where the emphasis is put on the receiver which is realized using a synchronized oscillator.
Abstract: Optical fibers constitute an attractive alternative to conventional wiring for the distribution of high spectral purity microwave signals. The main application here investigated is the remote synchronization and control in Ku-band of the elements of an onboard active antenna. The emphasis is put on the receiver which is realized using a synchronized oscillator.
6 citations