A single GaAs MMIC for up and down conversion in PCN transceivers

An active GaAs MMIC converter has been designed for dual operation in up and down frequency conversion, aiming at various applications in wireless telecommunication systems. The circuit design was specified for use in PCN transceivers, operating over the 200 MHz to 2.5 GHz RF band, with 45 to 500 MHz IF band. The converter design was based on a Gilbert (1968) cell structure, employing GaAs MESFET differential pairs and active baluns. Optimized characteristics were achieved by simulating the schematic and layout topologies, using the HP-EESOF CAD environment. The converter was sent for fabrication at the GEC-Marconi foundry, UK, as part of the former Eurochip Multi-Project-Wafer (now Europractice MPW). Measured results of the converter confirm its capability of delivering gain and presenting high isolation between ports, as well as adequate compression characteristics, in both transceiver pathways. Such results distinguish this device from commercially available mixers for PCN systems, for its dual operation as up and down converter and for its flexibility of use.