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This paper proposes an adaptive radio frequency (RF) stealth beamforming for frequency diverse array (FDA) radar using spoiled frequency increments. Since active radars are highly visible to intercept receivers, traditional high-gain phasedarray antenna beam is replaced by a series of low-gain FDA beam with nonlinear frequency increments to reduce the system visibility, and it achieves the same performance...
Recent advancements in low power micro sensors and wireless network technology have enabled a host of new sensor network applications. One such application is to perform multicast collaborative beamforming from a stationary airborne wireless sensor network. Such a network will be able to broadcast a signal to multiple distributed receivers simultaneously. Collaborative beamforming from such a network...
This article puts forward a method for codebook design to support beamforming mechanism in a 60GHz millimeter-wave wireless communication environment. The codebook is designed with only phase shifting but not any amplitude adjustment to meet the low power consumption requirement. IEEE802.15.3c beam MRA (main response axis) directions are taken as the original version to make curve fitting, so that...
A digital beamforming (DBF) prototype that uses compact and low cost Balanced Antipodal Vivaldi Antenna (BAVA) array and SiGe based-receiver is presented. An example is given for a Ku-band DBF system that demonstrates simultaneous reception of two or more full motion videos in a portable device.
A 16-channel digital wideband phased array without antenna is characterized using impulse response measurement. A chirp signal is used as probing signal. By careful chirp design, impulse response at sub-band is measured for all the channels. Spectral domain response showing dispersive phase and magnitude reveals significant imbalance among the channels. Based on time reversal technique principle,...
This paper describes a multi-channel S-band radar receive system designed as a laboratory testbed system for studying wideband radar array signal processing. The receive array was designed using a combination of low-cost commercial-of-the-shelf components and a custom-designed surface-mount printed circuit board assembly. It has been tested using LFM-CW waveforms with a center frequency of 2.4 GHz...
Fully integrated frequency-phase generators for a 6-18 GHz wide-band phased-array receiver element are presented that generate 5-7 GHz and 9-12 GHz first LO signals with less than -95 dBc/Hz phase noise at 100 kHz offset. Second LO signals with digitally controllable four-quadrant phase- and amplitude spread with better than 3deg resolution are generated and allow removal of systematic reference clock...
A fully integrated receiver front-end circuit for a 4:1 time division multiplexing of RF signals from an antenna array is introduced. The switching necessary for multiplexing is implemented as an array of low noise amplifiers operating at 2.4 GHz with selectable outputs. The circuit includes on-chip input and output matching networks. A digital controller for rotating through the amplifier inputs...
The channel outputs are sampled on nonuniform sampling sets, and an analysis of the decorrelation based on nonuniform sampling (NUS) is investigated. It is demonstrated that MUSIC algorithm with NUS of various array elements may be capable of selecting the signal of interesting including the coherent group. NUS in the time domain is equivalent to alter the relative distance between sensors and leads...
This paper studies efficient complex valued matrix manipulations for multi-user STBC-MIMO decoding. A novel method called Alamouti blockwise analytical matrix inversion (ABAMI) is proposed for the inversion of large complex matrices that are based on Alamouti sub-blocks. Another method using a variant of Givens rotation is proposed for fast QR decomposition of this kind of matrices. Our solutions...
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