An improved capacitive loading method for miniaturization of 0 dB forward-wave directional couplers is demonstrated. The method enables to miniaturize the coupler to have a predetermined characteristic impedance, eliminating the need for additional impedance transformers and therefore allowing for a substantial improvement in the degree of miniaturization. Experimental results for a 0 dB coupler at 5.0 GHz are provided. The demonstrated miniaturization rate of 89.4% is higher than previous methods, along with the widest fractional bandwidth and the minimum insertion loss.
Bibliographical noteFunding Information:
Manuscript received September 30, 2010; revised December 31, 2010; accepted January 07, 2011. Date of publication March 10, 2011; date of current version April 08, 2011. This work was supported by the Defence Nano Technology Application Center Program of the Defense Acquisition Program Administration and the Agency for Defense Development of Korea, and by the CPRC Program of Korea Communications Commission (KCC) supervised by the Institute for Information Technology Advancement (IITA) (IITA-2009-C1091-0901-0007).
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Electrical and Electronic Engineering