This paper presents an improved design of a Yjunctions power divider operating at the X-band based on the substrate integrated waveguide (SIW) technology. By cutting a rectangular slot and adding an isolating resistor helps absorbing the radiated signal, thus improving the isolation performance. The divider is designed on a cost-effective 30-mil RO4350B substrate. The simulated results on both Keysight ADS and CST Microwave Studio simulators show a good isolation of better than 10 dB whereas the insertion loss is below 1.0 dB, the return losses of two output ports are better than 10 dB. The other performance such as the amplitude and phase balances are 0,3 dB and 4,6o with a fractional bandwidth of 40%.

*This research is partly funded by VIET ELECTRONIC TECHNOLOGY SOLUTIONS CO., LTD.