A broadband upconverter IC

The authors describe the design and performance of a single-chip upconverter IC consisting of a doubly balanced dual-gate FET mixer, a four-stage local oscillator (LO) amplifier, and a single-stage IF amplifier. Due to a novel mixer topology, the input passband of the converter extended from DC to 5 GHz, the LO frequency range was 8 GHz to 16 GHz, and the IF output frequency range was 8 to 10 GHz. The primary design goals for this upconverter were a high third-order intermodulation intercept point (IP/sub 3/) and good spurious-response rejection. Advanced FET models were used to optimize the circuit's intercept points. The converter exhibited an IP/sub 3/ of 23.5 dBm across most of the band; second-order intercept points (IP/sub 2/) for spurious responses were greater than +40 dBm.<>