A system for cancelling leakage interference in phased array antenna based on microwave photonic, wherein the system consists of a signal generation unit, a splitter, a beamforming unit, a transmitting phased array antenna, a receiving phased array antenna, a microwave photonic channel construction array, a control unit, a combiner array, and a signal receiving unit;
- the signal generation unit, the splitter, the beamforming unit, and the transmitting phased array antenna are sequentially connected by cables or microstrip lines;
- the signal generation unit is used to generate a microwave signal, which transmits to the splitter;
- the splitter divides the microwave signal generated by the signal generation unit into two parts, which transmit to the beamforming unit as transmitting signal and to the microwave photonic channel construction array as a reference signal for cancelling leakage interference;
- the beamforming unit adjusts the amplitude and phase of the transmitting signal of each antenna element, thereby achieving function of beamforming;
- the control unit controls an array of amplitude adjustment unit, an array of optical delay adjustment unit, and an array of phase adjustment unit in the microwave photonic channel construction array to generate a matched reference signal, according to a leakage interference channel response of a receiving subarray;
- each combiner in the combiner array includes two input ports and one output port;
- the input ports are connected to a receiving antenna subarray and the microwave photonic channel construction array respectively;
- the output port is connected to the signal receiving unit;
- the signal receiving unit samples and quantizes received signal, analyses target information, and provides feedback to the control unit to achieve closed-loop feedback control;
- a multi-wavelength laser source is a multi-wavelength laser array or an optical frequency comb, which generates multiple optical carriers with a certain wavelength interval;
- an electro-optic conversion unit, consists of an electro-optic modulator and a driving control circuit;
- the electro-optic conversion unit modulates the reference signal from the splitter onto multi-wavelength optical carriers to achieve electro-optic conversion;
- a wavelength division demultiplexing unit is a wavelength decomposer or a multi-channel optical filter, which is used to separate an optically carried microwave signals according to its wavelengths to subchannels of a microwave photonic channel construction unit;
- the optically carried microwave signals sequentially pass through the array of amplitude adjustment unit, the array of optical delay adjustment unit, and the array of phase adjustment unit in each subchannel;
- the array of amplitude adjustment unit consisting of M-path adjustable optical attenuators, which have the function of adjusting the amplitude of the optically carried microwave signals;
- the array of optical delay adjustment unit consisting of M-path adjustable optical delay lines, which have the function of adjusting the delay of the optically carried microwave signal;
- the array of phase adjustment unit array consisting of M-channel adjustable phase shifters based on microwave photonic, which have the function of adjusting the phase of optically carried microwave signals;
- a wavelength division multiplexer unit is a wavelength multiplexer or a coupler, which is used to combine the optically carried microwave signals and transmit them to an opto-electric conversion unit;
- the opto-electric conversion unit is a photodetector having opto-electric conversion function.