Abstract: An antenna arrangement comprising: a ground plane; a ground point connected to the ground plane; a feed point; a ?/2 antenna element connected to the ground point and to the feed point and extending between the ground point and the feed point as a loop that defines an area; and a ?/4 antenna element located within the area.

Abstract: An antenna arrangement comprising: a ground plane; a ground point connected to the ground plane; a feed point; a ?/2 antenna element connected to the ground point and to the feed point and extending between the ground point and the feed point as a loop that defines an area; and a ?/4 antenna element located within the area.

Abstract: A transceiver for a portable radio communication apparatus comprising a receiver for receiving a signal at a received frequency and including a local oscillator, a transmitter being operable to transmit at a transmission frequency, said transmission frequency being offset from, and aligned to, the received frequency by a predetermined frequency spacing, the transmitter including a mixer having a first port for inputting said transmission frequency signal and a second port for inputting the local oscillator signal, and comprising means for rectifying the input local oscillator signal to provide a conductance waveform at a multiple of the local oscillator signal and means for mixing said transmission frequency signal with the conductance waveform at said multiple of the local oscillator signal frequency for down-converting the transmission frequency signal to an intermediate frequency signal.

Abstract: A sub-harmonically pumped mixer has an anti-parallel diode pair switchable at twice the local oscillator frequency. Preferably, there are provided dual anti-parallel diode pairs. The local oscillator is coupled to the diode pairs by means of an unbalanced to balanced transformer. The balanced output of the transformer is coupled to the diodes and provides anti-phased signals to respective ones of anti-parallel diode pairs.