An FR4-Based Self-Packaged Full Ka-Band Low-Loss 1:4 Power Divider Using SISL to Air-Filled SIW T-Junction

An FR4-based full
Ka
-band 1:4 passive power divider using substrate integrated suspended line (SISL) technology is presented in this letter and it achieves a relatively low insertion loss. A SISL to air-filled substrate integrated waveguide (SIW) T-junction with an iris structure is proposed as the first stage of the divider to obtain wideband matching, and a bandwidth of 61.7% is achieved. The power-handling capability of the power divider is studied. A back-to-back 1:4 power divider was fabricated, and the measured results agree well with the simulated ones. From 25.2 to 40 GHz, i.e., a 45.5% fractional bandwidth, the measured return loss is better than 15 dB, and the measured insertion loss is less than 1.2 dB. Moreover, the isolation performance is improved from 2.5 to 15 dB by adding three ports connected with the load resistor.