Open-Loop Folded Ring Mimics Photonic Band-Gap Device

An open-loop folded microstrip ring resonator is practically demonstrated to exhibit a photonic band-gap (PBG) phenomenon. This is due to the fact that impedance discontinuity at the gap introduces multiple reflections with phase correlation that generates a PBG response. The physical dimensions of this device are significantly smaller than other conventional microstrip PBG structures. Such a device can be easily integrated with other microwave devices without severely affecting space requirements