Improved design of microstrip air-bridges

The mismatch caused by the presence of an air-bridge can be reduced by introducing microstrip square pads at both ends of the air-bridge. The characteristics of the air-bridge and its approximate equivalent circuit are investigated. Two solutions are found for the sizes of pads when the length and width of the air-bridge are fixed. An approximate design procedure for the improved air-bridge is proposed for the first time. Simulation results and measurements of a 1-GHz air-bridge confirm the improvement of the air-bridge. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 246–255, 2003.