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In this paper, we present the performance of a dual-band textile CPW antenna under different bending and crumpling conditions. The performance of the antenna is presented together with an electromagnetic band gap material (EBG) to improve the wearable antenna performance. The input impedance and radiation pattern are investigated based on numerical and experimental methods at 2.45 GHz and 5.8 GHz.

Time-switched arrays use simple binary switches in the element feed network to allow various beamforming functions to be implemented. Sequential switching sequences applied across the face of the array generate multiple main beams at different harmonic frequencies and at different angular directions. An analysis of time-switched arrays is presented and various modulation schemes for multiple beam steering are examined. Numerical results are presented for beam steering using a 16 element linear time-switched array.

A novel adaptive beamforming algorithm is proposed based on a uniformly spaced linear antenna array by constraining its weight vector to a specific conjugate symmetric form. Two sets of constraints (linear and quadratic) are imposed on the beamformer while minimizing its output variance. Compared to the traditional linearly constrained minimum variance (LCMV) beamforming algorithm, the proposed one can achieve a faster convergence speed and a higher steady state SINR (signal to interference plus noise ratio) and is less sensitive to the change of its stepsize in terms of the final output SINR. Simulation results verify the effectiveness of the proposed algorithm.

Numerical simulation has been carried out to assess the effects of different source antenna locations on electric field distribution within a vehicle cabin at 2400 MHz. Only fixed onboard antennas mounted within the vehicle cabin are considered. The car model contains only metallic parts and ignores dielectric furnishings. Localised electric field visualizations within the vehicle cabin are obtained using simulated 2D cut-planes. They are complemented by histograms describing the distribution of electric field amplitudes within the vehicle cabin volume relative to a 1W power source. The averaged electric field levels obtained were used to compare the effectiveness of the source antennas placed in various locations within the vehicle.

Cognitive Radio systems require antennas and microwave components to be actively tuned for different parts of the frequency spectrum. In this paper results of a study of three antenna tuning techniques are presented here. The first tunable antenna is a liquid crystal (LC) tuned microstrip patch antenna operating in the 2 GHz range. The simulated tuning range is 8% while the measurements showed a range of 3.8%. Losses in the LC material at these frequencies give rise to antenna efficiencies ranging from 25% to around 7% when the LC is in the unbiased state. The second antenna is a reconfigurable PIFA which is able to cover 7 frequency bands by controlling the combination of 4 MEMS switches mounted on the radiator. The third antenna is a dual-port antenna which is comprised of two capacitive-fed plates sharing one lower-band patch, operating for 5 mobile phone bands.