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A single layer wideband SIW-fed differential patch array is proposed in this paper. A SIW-CPS-CMS (substrate integrated waveguide - coupled lines - coupled microstrip line) transition is designed and has a bandwidth of about 50%, covering the E-band and W-band. The differential phase deviation between the coupled microstrip lines is less than 7.5° within the operation band. A 1×4 array and a 4×4 array...
A 4-element uniform Vivaldi antenna array fed by a novel ridge SIW (RSIW) feed network has been developed using a two-layer substrate. The low cost planar RSIW divider is designed for wide band operation to sustain the inherent wide bandwidth of the Vivaldi array that is fed by a very wide band GCPW to RSIW transition as well. The proposed antenna structure has been fabricated and showed good radiation...
In this paper, a X-band Cavity-Backed Slot Antennas (CBSA) is proposed. With the multi-layer Dielectric Resonator cover, the bandwidth and gain are improved significantly comparing with traditional slot antenna. The −10dB return loss bandwidth is almost 40% with the gain ranging from 5dB to 9.5dB. Based on the element study, a 2 ×2 antenna array is designed with the return loss bandwidth of 34% and...
The noise background of small aperture sensor array is spatial color noise for underwater sonar detection system. A super-directive beamform in frequency domain (FSD) method is proposed to solve the problem that the array gain of super-directive beamform cannot reach maximum when there exists error in the estimated noise matrix under spatial color noise background. The wideband received data are divided...
A simple wideband and dual-polarized array is proposed. It is comprised of connected crossed hollow bowtie antennas. The element design can achieve an impedance bandwidth about 57% (from 1.5 to 2.7GHz). The 3dB gain bandwidth of the element is nearly 70% (from 1.35 to 2.75GHz). Dual polarization can be realized with a the good isolation (−25dB) between different polarization ports. A Γ - shape feed...
In Release 8 (R8) LTE a 4 antenna codebook was designed primarily with a uniform linear array (ULA) in mind. The consequence is that when using an array at the base other than a ULA (for example a uniform circular array (UCA)) the performance with codebook feedback will be degraded relative to a codebook optimized for that array structure. In this paper methods for improving the performance of LTE...
Recently, Vivaldi antenna elements have been used by Roke to realize direction finding antenna array solutions for full horizon coverage. Unfortunately the Vivaldi elements used previously have certain limitations which make them unsuitable for use in a compact DF (direction finding) antenna array, in particular how the element phase centre position tracks with frequency. This paper describes the...
In this paper we present the design, fabrication and demonstration of an X-band phased array capable of wide-angle scanning. A new non-symmetric element for wideband tightly coupled dipole arrays is integrated with a low-profile microstrip balun printed on the array ground plane. The feed connects to the array aperture with vertical twin-wire transmission lines that concurrently perform impedance...
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,...
In this paper, we expand the current sheet array (CSA) concepts, proposed by Munk et al. to design, fabricate and measure a wideband phased array with an integrated conformal balun. A unique feature of the proposed array and feed is its low-profile planar layered PCB construction. Specifically, a single microwave laminate is used for the array aperture and another (underneath) supports all associated...
The additional estimation error introduced by the use of finite ground planes is evaluated numerically for two types of conventional direction finding (DF) systems. The analysis reveals that commonly accepted ground plane dimensions result in degraded estimation accuracy when the incoming signals are of unknown polarization.
A new wideband antenna for airborne SAR applications has been presented. It is based on a geometry that gives a stable phase center. It allows to have a rejection of the ground response ambiguity of more than 34 dB. Its bandwidth (defined for a S11 les -8 dB, with a gain ges 5 dB) is 245-390 MHz (45%). Further works will include the improvement of the S11, along with a size reduction of the LPDA to...
A comparison of three phased array concepts that can be used to reduce the frequency dependence of the radiation characteristics of very wideband phased arrays is presented. The three concepts consist of a multiband array, a frequency tapered array and an array with varying element sizes and element distances. Parameters such as aperture area, number of elements, gain, effective radiated power (ERP)...
A new method for wideband spatio-temporal processing in the context of clutter mitigation and target detection is addressed in this paper. The frequency dependent, spatio-temporal steering vectors, are separated using a series expansion that depends on a sequence of Bessel function terms, and this is used to focus data vectors corresponding to various frequency components to a single frequency component...
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