A feeder device for supplying a radio frequency signal to an adaptive antenna array comprising a plurality of antenna elements, said feeder device comprising: a plurality of signal dividers, each of said signal dividers comprising: an input port for receiving said radio frequency signal, an output port, a further output port and a variable impedance; wherein said signal divider is configured to divide said input signal and direct said divided signals towards said variable impedance; said divided signals are at least one of reflected to said output port and transmitted to said further output port, said degree of reflection and transmission depending on a value of said variable impedance, said degree of reflection and transmission being variable between substantially all reflection and substantially all transmission; wherein said signal divider is configured such that phase shifts are introduced to signals travelling between ports, said phase shifts being such that said divided signals received at said output port and said further output port constructively interfere and signals received at outer ports of said signal divider other than said output ports are out of phase and destructively interfere; said output and said further output ports of at least one of said at least one signal divider are configured to supply signals to respective antenna elements of said antenna array; wherein said plurality of signal dividers are arranged in a cascade, said cascade comprising: an input signal divider configured to receive said radio frequency input signal and direct said signal to at least one of said output port and said further output port of said input signal divider; further signal dividers each configured to receive at an input a signal from one of said out port and said further output port of one of said signal dividers in a higher level of said cascade; and a plurality of output signal dividers each being configured to direct a received input signal via at least one of said output port and said further output port to respective antenna elements of said antenna array. an input port for receiving said radio frequency signal, an output port, a further output port and a variable impedance; wherein said signal divider is configured to divide said input signal and direct said divided signals towards said variable impedance; said divided signals are at least one of reflected to said output port and transmitted to said further output port, said degree of reflection and transmission depending on a value of said variable impedance, said degree of reflection and transmission being variable between substantially all reflection and substantially all transmission; wherein said signal divider is configured such that phase shifts are introduced to signals travelling between ports, said phase shifts being such that said divided signals received at said output port and said further output port constructively interfere and signals received at outer ports of said signal divider other than said output ports are out of phase and destructively interfere; said output and said further output ports of at least one of said at least one signal divider are configured to supply signals to respective antenna elements of said antenna array; wherein said plurality of signal dividers are arranged in a cascade, said cascade comprising: an input signal divider configured to receive said radio frequency input signal and direct said signal to at least one of said output port and said further output port of said input signal divider; further signal dividers each configured to receive at an input a signal from one of said out port and said further output port of one of said signal dividers in a higher level of said cascade; and a plurality of output signal dividers each being configured to direct a received input signal via at least one of said output port and said further output port to respective antenna elements of said antenna array. an input signal divider configured to receive said radio frequency input signal and direct said signal to at least one of said output port and said further output port of said input signal divider; further signal dividers each configured to receive at an input a signal from one of said out port and said further output port of one of said signal dividers in a higher level of said cascade; and a plurality of output signal dividers each being configured to direct a received input signal via at least one of said output port and said further output port to respective antenna elements of said antenna array.