A balanced antenna system comprising a radiator connected to an integrated matching circuit and balun, wherein: i) the radiator comprises a first radiating element and a second radiating element each having a respective feed line (214, 222); ii) the matching circuit comprises a first impedance-matching circuit and a second impedance-matching circuit; iii) the feed line of the first radiating element is connected to the first matching circuit and the feed line of the second radiating element is connected to the second matching circuit; and iv) the first and second matching circuits (252, 254) and the balun are integrated and configured to produce a phase difference of substantially 180° between the first and second feed lines (214, 222) across an operating bandwidth of the antenna system; characterised in that the first and second impedance matching circuits (252, 254) each have a respective input (Z b1, Z b2) and a respective output; the balun comprises first and second inputs for input of first and second balanced signals, circuitry to convert the first and second balanced signals to a single unbalanced signal, and a single output (Z U) for output of the unbalanced signal; the feed line of the first radiating element is connected to the input (Z b1) of the first impedance-matching circuit and the feed line of the second radiating element is connected to the input (Z b2) of the second impedance-matching circuit; and the output of the first impedance-matching circuit is connected to the first input of the balun and the output of the second impedance-matching circuit is connected to the second input of the balun; wherein the first impedance-matching circuit comprises a first variable capacitor or varactor with an input and an output, a first inductor connected in series between the input (Z b1) of the first impedance-matching circuit and the input of the first variable capacitor or varactor, and a second inductor connected to the output of the first variable capacitor or varactor and shunted to ground, the output of the first variable capacitor or varactor also connected to the output of the first impedance-matching circuit, and the second impedance-matching circuit comprises a second variable capacitor or varactor with an input and an output, a third inductor connected in series between the input (Z b2) of the second impedance-matching circuit and the input of the second variable capacitor or varactor, and a fourth inductor connected to the output of the second variable capacitor or varactor and shunted to ground, the output of the second variable capacitor or varactor also connected to the output of the second impedance-matching circuit, so as to allow the matching circuit to be reconfigured to enable the respective first and/or second radiating elements (204, 216) to be tuned to different frequencies across the operating bandwidth of the antenna system; and wherein the balun comprises a high pass filter constituted by a third capacitor and a low pass filter constituted by an fifth inductor, the third capacitor and the fifth inductor connected in parallel branches from a T-junction which splits the unbalanced signal, and wherein the first impedance-matching circuit is provided between the high pass filter and the first radiating element and the second impedance-matching circuit is provided between the low pass filter and the second radiating element. i) the radiator comprises a first radiating element and a second radiating element each having a respective feed line (214, 222); ii) the matching circuit comprises a first impedance-matching circuit and a second impedance-matching circuit; iii) the feed line of the first radiating element is connected to the first matching circuit and the feed line of the second radiating element is connected to the second matching circuit; and iv) the first and second matching circuits (252, 254) and the balun are integrated and configured to produce a phase difference of substantially 180° between the first and second feed lines (214, 222) across an operating bandwidth of the antenna system;