Apparatus for transmitting and receiving signals in a wireless communication network, the apparatus comprising: a transmit antenna (121; 211; 711; 811; 911) configured to transmit signals to the wireless communication network; and a receive antenna (122; 212; 712; 812; 912) configured to receive signals from the wireless communication network; characterised in that the apparatus is configured to operate in a Frequency Division Duplexing mode in which the transmit antenna is configured to transmit signals at a first frequency and the receive antenna is configured to receive signals at a second frequency different to the first frequency, and the apparatus comprises: an energy harvesting unit (213; 713a, 713b; 813; 913) configured to harvest electrical energy from a self-signal transmitted by the transmit antenna and received at the receive antenna; and a filter configured to receive an input signal from the receive antenna and separate the input signal into a first filtered signal having the first frequency and a second filtered signal having the second frequency, such that the first filtered signal includes the self-signal transmitted at the first frequency by the transmit antenna, wherein the energy harvesting unit is configured to receive the first filtered signal from the filter and harvest the electrical energy from the first filtered signal. a transmit antenna (121; 211; 711; 811; 911) configured to transmit signals to the wireless communication network; and a receive antenna (122; 212; 712; 812; 912) configured to receive signals from the wireless communication network; characterised in that the apparatus is configured to operate in a Frequency Division Duplexing mode in which the transmit antenna is configured to transmit signals at a first frequency and the receive antenna is configured to receive signals at a second frequency different to the first frequency, and the apparatus comprises: an energy harvesting unit (213; 713a, 713b; 813; 913) configured to harvest electrical energy from a self-signal transmitted by the transmit antenna and received at the receive antenna; and a filter configured to receive an input signal from the receive antenna and separate the input signal into a first filtered signal having the first frequency and a second filtered signal having the second frequency, such that the first filtered signal includes the self-signal transmitted at the first frequency by the transmit antenna, wherein the energy harvesting unit is configured to receive the first filtered signal from the filter and harvest the electrical energy from the first filtered signal. an energy harvesting unit (213; 713a, 713b; 813; 913) configured to harvest electrical energy from a self-signal transmitted by the transmit antenna and received at the receive antenna; and a filter configured to receive an input signal from the receive antenna and separate the input signal into a first filtered signal having the first frequency and a second filtered signal having the second frequency, such that the first filtered signal includes the self-signal transmitted at the first frequency by the transmit antenna, wherein the energy harvesting unit is configured to receive the first filtered signal from the filter and harvest the electrical energy from the first filtered signal.