A novel low-loss slow-wave microstrip structure

A low-loss slow-wave microstrip line using a periodic structure in the grou nd plane is presented. The periodic structure is realized with metal pads e tched in the ground plane connected by thin lines to form a distributed LC network. The slow-wave factor is demonstrated to be 1.2-2.4 times larger th an that of conventional microstrip lines over a wide frequency range. Due t o the unique design of the structure, low insertion loss comparable to conv entional microstrips has been achieved. The proposed structure is easier to fabricate than other slow-wave devices which require multilayer substrates or very fine features.