Research On CPW Air Bridge And Its Application In Directional Coupler

Air bridges are widely used in MIC and MMIC, it will cause occur slot line pattern.Air bridgeis a method of cross connection,which has low parasitic effects,it can be used to suppress the slotline pattern in CPW.Compared with the traditional welding technology,it has obviousadvantages.CPW directional coupler is used more widely than the microstrip directional coupler foreasier integration, smaller size,lower cost and weaker dispersion.Because the air bridge can inhibitslot line pattern, the research on CPW air bridge and its application in CPW directional coupler hasgreat significance and engineering value.This paper studies the CPW air bridges,two methods for improving the transmissioncharacteristics of the air bridge and the CPW air bridge on the coplanar waveguide directionalcoupler. First,the geometrical parameters of the CPW air bridge is analyzed and studied,and thelocation and number of the CPW air bridge is also disscussed.Through the comparison oftransmission characteristics of CPW air bridge A and CPW air bridge B, the air bridge typeaccording to different requirements can be selected.The transmission characteristics of CPW withair bridge becomes bad,this paper proposes to improve the transmission characteristics of CPW withair bridge by ground floor opening and the air bridge drilling. The simulation results show that thetransmission properties of CPW improved a lot. The result is better when uses two kinds of metheds.Finally, the effects of different types of CPW air bridge on CPW directional coupler is discussed.CPW directional coupler with air bridge can eliminate inconsistency caused by gound, it also caninhibit the directional coupler of slot line mode, broaden the bandwidth and improve the portmatching and isolation.