This invention concerns a sub-harmonic homodyne mixer suitable for operation at the millimeter waveband (MMW); for instance the 60 GHz RF radio band. The mixer comprises: A first pair of transistors connected together with common source and common drain, and having an input port across their gates to receive the in-phase voltage signal from a local oscillator. A second pair of transistors also connected together with common source and common drain, and having an input port across their gates to receive the quadrature voltage signal from the local oscillator. Wherein, an input voltage port is defined directly across the common sources of the first and second pairs of transistors, and an output voltage port is defined between the common drains of the first pair of transistors and the common drains of the second pair of transistors. According to another aspect the present invention is a transceiver comprising a mixer according to the first aspect.