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Design of a tapered CPW-fed wideband antenna and its application to multi-channel transmission using a hybrid wireless communication system

Abstract:

A tapered Coplanar Waveguide (CPW)-fed wideband antenna with a nearly omnidirectional radiation pattern in the H-plane and a stable dipole-like radiation pattern for the E-plane is presented. The proposed antenna operates in two wide bands centered at 3.3 and 5 GHz. Furthermore, the antenna structure consists of a tapered feed line, which provides an impedance transformation from the quarter-wave monopole impedance to the 50 Ω input characteristic impedance. Also, two trapezoidal ground planes are added between the monopole and the CPW to achieve impedance matching. Variations in the antenna dimensions are included to monitor the bandwidth and to evaluate the efficiency of impedance matching. Moreover, in order to evaluate the performance of the proposed antenna, a hybrid wireless communication system is used to simultaneously transmit two analog TV signals. These TV signals modulate two microwave subcarriers located at 3.3 and 5 GHz. The resulting multiplexed signal is propagated between two antennas that are separated by a distance of 1 m. The modulated subcarriers are transmitted over an optical link of 30 km by using an optical communication system based on external modulation. The signal at the end of the optical link is successfully recovered by using a conventional demodulation scheme.