HIPERLAN (High Performance Radio Local Area Networks) is an emerging European standard for wireless local area networks with an in air data rate of 23.5 Mbits/sec. This paper details the design manufacture and measured performance of two application specific GaAs MMICs which form the majority of the 5.2 GHz RF front end. One MMIC is a power amplifier with level control and the other is an up/down-converter with on chip VCO. These are the first GaAs MMICs designed specifically for the HIPERLAN standard