A Compact Four-pole Cross Couple Square Open Loop with Asymmetric Feed

In this paper, a compact four-pole cross couple square open loop with asymmetric feed is proposed to develop the microstrip square open loop resonators bandpass filter. The filter is based upon a square open loop resonator consisting of two identical patches which is attached to the inner corner of the square open loop for size reduction. The compact miniaturized four poles square open loop resonators is used to design filters for imt-2000 bands application. A prototype filter is designed at 1950 mhz and simulated by ie3d. The measurement of fabricated structure proposes 60 mhz bandwidth and 3.0 db insertion loss. It is very useful for applications in communication systems.