A compact artificial transmission line structure using LTCC technology and its applications

A compact artificial transmission line (ATL) structure using LTCC technology together with its applications are presented in this paper. Thanks for the 3-D fabrication capability, the proposed structure can be designed almost in-line with respect to the 50 Ohm microstrip line and leads to a very compact size. An ATL prototype operating in the C-band is then designed and implemented to a microstrip-to-coplanr strip (CPS) transition, as well as a quasi-Yagi antenna. The transition exhibits a relative 3-dB bandwith of 42.9%, ranging from 5.3 GHz to 8.2 GHz. The minimum insertion loss at the center frequency is less than 1.2 dB. The quasi-Yagi antenna exhibits a relative bandwidth of 27.8% from 6.2 GHz to 8.2 GHz. The gain the of the antenna is 6.2 dBi and pointing to its boresight. The proposed ATL structure is very suitable for those compact in-package front-end designs.