Design of Various Compact Branch-Line Couplers by Using Artificial Transmission Lines

In this paper, a compact and easy to fabricate branch-line couplers, which can be used for tight and weak couplings with high directivity, is proposed. For these purpose, various artificial transmission lines (ATLs) are incorporated. Design of 3 dB and 10 dB couplers are designed and their characteristics are measured. Good electrical performance and circuit miniaturization indicate the validity of the present theory