Wideband planar printed antenna with end-fire radiation pattern

A compact printed planar antenna fed asymmetrically by a 50 Ω microstrip line is presented. This novel structural configuration is derived from conventional printed rectangular monopole, by introducing feed-line asymmetry to offer octave band end-fire radiation patterns. A rectangular ground plane of considerably small length and modified in shape with two symmetrical bevel slots on the upper edge, illustrate significant improvement in the input impedance matching of the antenna over the operating bandwidth. The influence of the length of the radiation patch and thickness of the dielectric substrate on the gain of the antenna is explored numerically. By linearly tapering the radiation patch, significant improvement in gain is observed. Both numerical and experimental reflection coefficient results confirm that the proposed antenna presents an impedance bandwidth of 94% for reflection coefficients less than -10 dB. The measured results present an optimum gain of 11.8 dBi and stable unidirectional radiation patterns. This novel antenna has wide impedance bandwidth, compact size and reasonably high gain, suitable for various broadband applications including point-to-point communication. The antenna is simple in structure with very few design parameters.