This paper presents a compound electronic counter-countermeasure (ECCM) technique for frequency-modulated continuous-wave (FMCW) radars to counter electronic countermeasure (ECM) techniques such as coherent spoofing, non-coherent spoofing, and digital radio frequency memory (DRFM) jamming. The proposed technique is based on phase coding in slow time and checking the initial phase of the baseband return signal. A measurement setup was built and operated between 4.3-4.5 GHz for experimental validation. An RF cable of length 12 m was used to emulate the target. The experimental results were analyzed using MATLAB to demonstrate the effectiveness of the ECCM technique in different jamming scenarios. The results indicate that the proposed ECCM technique using phase coding can provide a satisfactory performance in different jamming scenarios. The proposed ECCM technique offers several advantages over existing methods. First, the technique does not entail any frequency bin changes in slow time period, thereby conferring processing benefits. Second, it poses challenges to jammer system in terms of predicting the initial phase of the beat signal. The proposed technique is expected to provide better protection against malicious attacks for FMCW radars.