A switching circuit for an active mixer; the switching circuit comprising a first pair of switching devices (M 1a, M 1b, 710,720) and a second pair of switching devices (M 2a, M 2b, 730,740), the first and second pairs of switching devices being arranged such that: a first switching device (M 1a, 710) of the first pair of switching devices is operably coupled in series with a first switching device (M 2a, 730) of the second pair of switching devices between an input node of the switching circuit at which an input current comprising a first input frequency signal is received and a first of a pair of differential output nodes of the switching circuit; a second switching device (M 1b, 720) of the first pair of switching devices is operably coupled in series with a second switching device (M 2b, 740) of the second pair of switching devices between the input node of the switching circuit and a second of the pair of differential output nodes of the switching circuit, the first pair of switching devices (M 1a, M 1b, 710,720) are controlled by a second input frequency signal, the second input frequency signal comprising a differential signal pair (715, 725), and the first and second switching devices (M 1a, M 1b, 710,720) of the first pair of switching devices are controlled by respective complementary signal components of the differential signal pair (715, 725) of the second input frequency signal; the second pair of switching devices (M 2a, M 2b, 730,740) are controlled by a phase-shifted counterpart (735,745) of the second input frequency signal, and the first and second switching devices (M 2a, M 2b, 730,740) of the second pair of switching devices are controlled by respective complementary signal components of a differential signal pair of the phase shifted counterpart of the second input frequency signal; and a common node between the first switching devices (M 1a, M 2a, 710,730) of the first and second pairs of switching devices is electrically coupled to a common node between the second switching devices (M 1b, M 2b, 720,740) of the first and second pairs of switching devices. a first switching device (M 1a, 710) of the first pair of switching devices is operably coupled in series with a first switching device (M 2a, 730) of the second pair of switching devices between an input node of the switching circuit at which an input current comprising a first input frequency signal is received and a first of a pair of differential output nodes of the switching circuit; a second switching device (M 1b, 720) of the first pair of switching devices is operably coupled in series with a second switching device (M 2b, 740) of the second pair of switching devices between the input node of the switching circuit and a second of the pair of differential output nodes of the switching circuit, the first pair of switching devices (M 1a, M 1b, 710,720) are controlled by a second input frequency signal, the second input frequency signal comprising a differential signal pair (715, 725), and the first and second switching devices (M 1a, M 1b, 710,720) of the first pair of switching devices are controlled by respective complementary signal components of the differential signal pair (715, 725) of the second input frequency signal; the second pair of switching devices (M 2a, M 2b, 730,740) are controlled by a phase-shifted counterpart (735,745) of the second input frequency signal, and the first and second switching devices (M 2a, M 2b, 730,740) of the second pair of switching devices are controlled by respective complementary signal components of a differential signal pair of the phase shifted counterpart of the second input frequency signal; and a common node between the first switching devices (M 1a, M 2a, 710,730) of the first and second pairs of switching devices is electrically coupled to a common node between the second switching devices (M 1b, M 2b, 720,740) of the first and second pairs of switching devices.