Millimeter-wave broadband transition of substrate integrated waveguide on high-to-low dielectric constant substrates

In emerging millimeter-wave wireless applications at W- and E-bands, active components including LNA and power amplifier are preferred to be fabricated or surface-mounted on materials of high dielectric constant (like CMOS and MHMIC). On the other hand, antenna should be made on low dielectric constant substrate for the enhancement of gain and bandwidth. Therefore, the development of a wideband transition of transmission lines from high-to-low dielectric constant substrates becomes necessary. This paper presents a novel wideband transition of substrate integrated waveguide (SIW) on high-to-low dielectric constant substrates. The transition has a single layer structure which consists of a tapered high dielectric constant substrate that connects two SIWs. Thanks to the waveguide-based structure of the transition, it has a self-shielded configuration, and its noise interference is minimum. Simulated and measured results show that the bandwidth of the proposed transition covers almost the entire W and E bands with low insertion loss.