Design and Optimization of a Miniaturized Stub-Based Branch-Line Coupler at 900 MHz for GSM Applications
The branch-line coupler (BLC) is a four-port passive component widely used in wireless and microwave systems to divide or combine power equally with a 90° phase difference between its output ports. Because each branch of a conventional BLC is a quarter-wavelength long, the circuit becomes bulky at low frequencies such...