Frequency-Tunable and Pattern Diversity Antennas for Cognitive Radio Applications

Abstract

Frequency-tunable microstrip antennas, for cognitive radio applications, are proposed herein. The approach is based on tuning the operating frequency of a bandpass filter that is incorporated into a wideband antenna. The integration of an open loop resonator- (OLR-) based adjustable bandpass filter into a wideband antenna to transform it into a tunable filter-antenna is presented. The same technique is employed to design a cognitive radio pattern diversity tunable filter-antenna. A good agreement between the simulated and measured results for the fabricated prototypes is obtained. The radiation characteristics of each designed tunable filter-antenna are included herein.

A Review on Mutual Coupling Reduction Techniques in mmWaves Structures and Massive MIMO Arrays

“…With monopole radiating elements, the design seen in [136] shows a port-to-port isolation as good as 14 dB with a wide impedance bandwidth of 54.5% across 1.6-2.8 GHz and authors clearly state the effectiveness of this antenna to MIMO/diversity operation as a method to alleviate multipath environments. The open-loop resonator with curved slots observed in [137] was implemented with the pattern diversity technique. Aiming at cognitive radio applications, this tunable filter antenna has an isolation always better than 18 dB from 3.5 GHz up to 4.5 GHz.…”

MIMO antennas with diversity and mutual coupling reduction techniques: a review

“…The pattern reconfigurability is the effect of ground current alteration [44]. An open-loop resonator with curved slots [45], and I -shaped conductor [46] approaches were implemented with pattern diversity technique.…”

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“…Recently, frequency-tunable devices have been researched intensively for microwave applications, in an effort to meet the demands of numerous wireless services [1][2][3]. As well as frequency tunability, a microwave filter must be lightweight and compact [4].…”