A High Performance Tandem Coupler Using Substrate Integrated Suspended Line Technology

In this letter, a tandem coupler with high performance using substrate integrated suspended line (SISL) technology is proposed. Two weekly coupled single-section coupled lines are cascaded to form the 3 dB tandem coupler. With the compensation capacitors along the coupled lines, high directivity can be obtained. Using substrate integrated suspended line technology, the proposed tandem coupler has advantages of low loss, wide bandwidth, self-packaging, low cost, light weight and easy to fabricate on conventional printed circuit board process.