ANALYSIS AND DESIGN OF MICROSTRIP FILTERS USING PHOTONIC BAND GAP GROUND PLANE WITH FRACTAL PATTERN

摘要

In the present work, four different techniques are used in designing a microstrip low pass filters (LPF). These techniques include LPF with fractal defected ground structure (DGS), LPF with continuous Minkowiski fractal element, multi-stop band filter with discontinuous Minkowiski element, and finally a wide multi-stop filter with separated InterDigCap shape. A photonic band gap (PBG) in the ground plane of Minkowiski element and InterDigCap shape was designed to operate as a multifrequency band stop filter. With appropriate fractal geometry of Minkowiski and InterDigCap elements, a wide stop-band at different frequencies is obtained. However, with a continuous sinusoidal fractal slots a wide LPF can be obtained. The proposed fractal DGS can provide better band gap, and slow-wave characteristics. The numerical results show that a LPF of continuous and discontinuous fractal minkowiski elements in ground plane is obtained with a bandwidth 0-3 GHz for a slot width 0.5mm, However, if the slot width is taken equal 0.2 mm, the bandwidth is increased up to 10 GHZ. With suitable choice of number of elements, one can control the filter bandwidth. With a discontinuous fractal minkowiski and InterDigCap element in ground plane, the filter response is forced to have a stop band at resonance frequency of f_0 and repeated at 2f_0 and so on. The numerical results obtained using an analytical technique with the aid of a numerical package based on the method of moment (MOM). 【Keywords】Microstrip, Filters, Photonic Band Gap, Fractal.