A hybrid coil circuit comprising: a transformer comprising a first transformer winding and a second transformer winding, wherein a first centre tap is arranged on the first transformer winding, the hybrid coil circuit characterised by further comprising: a common mode choke comprising a first choke winding connected on its first side to a first end of the first transformer winding, a second choke winding connected on its first side to the first centre tap and a third choke winding connected on its first side to a second end of the first transformer winding, wherein all choke windings (26a-c) are magnetically coupled; an impedance matching device connected on a first end to a second side of the second choke winding, the impedance matching device being connected to ground; a first terminal of a first port being provided connected to a second side of the first choke winding; a second terminal of the first port being provided connected to a second end of the impedance matching device; a first terminal of a second port being provided connected to a second side of the third choke winding; a second terminal of the second port being provided connected to a second end of the impedance matching device; a third port being provided with respective terminals (22a-b) connected to either end of the second transformer winding; a first inductor arranged between the second end of the impedance matching device and the second terminal of the first port; and a second inductor arranged between the second end of the impedance matching device and the second terminal of the second port, wherein the first inductor and the second inductor are magnetically coupled. a transformer comprising a first transformer winding and a second transformer winding, wherein a first centre tap is arranged on the first transformer winding, the hybrid coil circuit characterised by further comprising: a common mode choke comprising a first choke winding connected on its first side to a first end of the first transformer winding, a second choke winding connected on its first side to the first centre tap and a third choke winding connected on its first side to a second end of the first transformer winding, wherein all choke windings (26a-c) are magnetically coupled; an impedance matching device connected on a first end to a second side of the second choke winding, the impedance matching device being connected to ground; a first terminal of a first port being provided connected to a second side of the first choke winding; a second terminal of the first port being provided connected to a second end of the impedance matching device; a first terminal of a second port being provided connected to a second side of the third choke winding; a second terminal of the second port being provided connected to a second end of the impedance matching device; a third port being provided with respective terminals (22a-b) connected to either end of the second transformer winding; a first inductor arranged between the second end of the impedance matching device and the second terminal of the first port; and a second inductor arranged between the second end of the impedance matching device and the second terminal of the second port, wherein the first inductor and the second inductor are magnetically coupled. a common mode choke comprising a first choke winding connected on its first side to a first end of the first transformer winding, a second choke winding connected on its first side to the first centre tap and a third choke winding connected on its first side to a second end of the first transformer winding, wherein all choke windings (26a-c) are magnetically coupled; an impedance matching device connected on a first end to a second side of the second choke winding, the impedance matching device being connected to ground; a first terminal of a first port being provided connected to a second side of the first choke winding; a second terminal of the first port being provided connected to a second end of the impedance matching device; a first terminal of a second port being provided connected to a second side of the third choke winding; a second terminal of the second port being provided connected to a second end of the impedance matching device; a third port being provided with respective terminals (22a-b) connected to either end of the second transformer winding; a first inductor arranged between the second end of the impedance matching device and the second terminal of the first port; and a second inductor arranged between the second end of the impedance matching device and the second terminal of the second port, wherein the first inductor and the second inductor are magnetically coupled.