Improvement of 3 dB microstrip directional coupler via cross coupling

A 3 dB microstrip directional coupler with a new coupling structure is introduced. Moreover, cross coupling is proposed for convenient use in practical engineering. The experimental results show that the device has better performances, such as ideal 3 dB power distribution, higher isolation in the isolated port, and a broader VSWR bandwidth. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 26: 151–153, 2000.