| Microwave Branches and Couplers |
| Microwave Branches and Couplers 4*l/4 Coupler and 6* l/4 Coupler Parallel Line Coupler Waveguide Couplers by Manfred Thumm and Werner Wiesbeck http://www.atic.nsu.ru/lpimti/sites/default/files/ch_03.4-2.8_branchcoupler40.pdf |