Broadband substrate-integrated waveguide T-junction with arbitrary power-dividing ratio

A novel broadband substrate-integrated waveguide (SIW) T-junction with an arbitrary power-dividing ratio is proposed. Three inductive posts are designed to adopt flexibility for the equal output T-junction to obtain a wide impedance bandwidth. To realise the unequal power-dividing ratio over a wide bandwidth, the SIW coupler is integrated with corner structures and a novel T-junction structure is formed. Three T-junctions with different power division ratios (1:1, 1:4 and 1:8) at a centre frequency of 6 GHz are simulated, fabricated and measured. The measured bandwidths are 60, 53 and 63.3%, respectively.