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A wireless electrocardiograph technology (WECG) which works on 2.5 GHz frequency band has been designed, implemented and evaluated in the actual environments both indoor and outdoor. WECG system has the benefit for improving the quality of the health care services especially for monitoring and evaluating people heart pulses record during the treatments. These are also practically useful to apply on...
Various types of internal antennas suitable for digital TV receiver have been investigated. These include rectangular plate loop structure, 1/2λ monopole, and L-dipole. Evaluations of the internal antennas were done, numerically and experimentally, to obtain some electrical properties such as S11, VSWR, gain and radiation pattern. All the fabricated antennas are incorporated inside the TV receiver...
Several horn antennas designed to operate at various frequencies including ISM bands (433 MHz, 0.9, 2.5, 3.5 and 5 GHz) and 1.8 GHz, respectively, are discussed. The preliminary construction of these antennas was firstly implemented through numerical computation using the available HFSS 11 optimizer tools. The optimization process was done by simply varying the size and angle of flares. The best design...
Yagi-Uda antennas are commonly used for data communications. Link budgets are calculated to ensure adequate fade margin. The presence of adjacent conducting material can affect antenna gain and impedance matching. Numerical modeling demonstrates that the gain of a 12 element Yagi-Uda is degraded by more than 2 dB when a human model is located in close proximity to the rear of the antenna. There are...
In this paper, the tuning and steering of a rectangular patch antenna is controlled by switching the patch and folded dipoles configuration. This reconfigurable antenna is controlled by the changing the voltage across a number of P.I.N. diodes in the parasitic elements. This antenna with the associated RF control unit forms a reconfigurable antenna which provides one solution to a number of communications...
A number of problems with p.i.n. diode switching circuits have been identified which might affect the Chen et al. results. A number of design requirements must be met to obtain ideal antenna performance. If switch activation symmetry is maintained, the centre frequency should not change. If a change in centre frequency is observed experimentally, then the cause might lie in imperfections inthe switching...
Radiation pattern symmetry of a switched parasitic smart antenna is important for full 360deg azimuthal coverage. The ideal symmetrical beam patterns are hard to achieve in reality due to a number of crucial problems related to the need for precision design and manufacture, and the accuracy of the supporting electronics. These factors are examined on this paper.
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