A Surface Mount 45 to 90 GHz Low Noise Amplifier Using Novel Hot-via Interconnection

Application of MMIC through-substrate via interconnects (“hot-vias”) to form a Chip Scale Package (CSP) and a Laminate Surface Mount Package (SMP) for a wideband millimeter-wave low noise amplifier (LNA) covering the full V & E-band waveguide bands were demonstrated for the first time. A wideband low noise amplifier MMIC covering 40-95 GHz range was successfully designed, assembled, and characterized with bondwire free chip interconnect technology. A broadband on chip matching network was a key element to maintain the intrinsic performance of the reference amplifier on the hot via MMIC. With this optimized hot-via RF transitions, compact full waveguide band CSP or SMP amplifiers can be directly mounted onto evaluation boards. The SMP LNA demonstrate a typical gain of > 15-dB and return losses > 15dB over 45-90GHz frequency range with little performance degradation compared to reference circuits probed with GSG front-side RF pads. To the author's knowledge, this optimized hot-via interconnection represents the highest bandwidth with extremely good return loss and lowest insertion loss for both V & E-band of any millimeter wave hot-via active circuits onto standard PCBs for a Surface Mount Package.