Abstract: An apparatus including a first port configured to couple to a first location on an antenna; a second port configured to couple to a second location on the antenna; a switch configured to switch between a first electrical configuration in which the first port is coupled to radio circuitry, and a second electrical configuration in which the second port is coupled to the radio circuitry; first reactive circuitry configured to impedance match the antenna with the radio circuitry at a first operational resonant frequency band; and second reactive circuitry, different to the first reactive circuitry, and configured to impedance match the antenna with the radio circuitry at a second operational resonant frequency band, different to the first operational resonant frequency band.

Abstract: An apparatus including a first port configured to couple to a first location on an antenna; a second port configured to couple to a second location on the antenna; a switch configured to switch between a first electrical configuration in which the first port is coupled to radio circuitry, and a second electrical configuration in which the second port is coupled to the radio circuitry; first reactive circuitry configured to impedance match the antenna with the radio circuitry at a first operational resonant frequency band; and second reactive circuitry, different to the first reactive circuitry, and configured to impedance match the antenna with the radio circuitry at a second operational resonant frequency band, different to the first operational resonant frequency band.

Abstract: An apparatus for a direction finding system is described. The apparatus includes at least three antenna elements. Each antenna element faces in a facing direction different than the other antenna elements. An individual antenna element has a substantially smooth polarization gain in the corresponding facing direction. Each antenna element includes a feeding branch, a parasitic branch and a back plate. The parasitic branch and the feeding branch are disposed in a first plane perpendicular to the feeding direction. The back plate is disposed in a second plane parallel to the first plane and the second plane is behind the first plane. The apparatus may be used to receive at least one signal from a transmitter. A distance and a direction from the apparatus to the transmitter may be determined based at least in part on the received at least one signal. Methods and computer readable media are also described.