A broadband microwave photonic front-end that suits for electronic warfare is proposed in this paper. Significant improvement in noise figure and spur-free dynamic range is accomplished by using double sideband suppressed carrier modulation and balanced coherent heterodyne detection. In the frequency bandwidth of 6~18GHz, a spur-free dynamic range up to 110dB·Hz2/3, a noise figure of 8dB, an amplitude consistency better than ±1dB and a phase consistency better than ±10° are implemented by using coherent detection, which makes it especially applicable for microwave photonic beam-forming, in addition to the RF transmission.