Slotline Switch Based on a Lattice Circuit

Slotline switches are required for many slotline applications, such as tunable slot antennas and slotline antenna feed networks. The current practice is to place a pin diode or MEMS device across the slot to create a short circuit when the switch is in the OFF state. In this letter, a slotline short circuit series stub is incorporated into a lattice circuit to achieve a switch with a theoretical 0 dB insertion loss, infinite isolation and infinite return loss over a narrow bandwidth. Measured results demonstrate a near zero insertion loss, approximately 40 dB of isolation and greater than 15 dB return loss at 4.25 GHz, with an approximate 40% bandwidth defined by return loss and isolation greater than 10 dB.