This paper presents an experimental study to evaluate the effects of antenna radiation parameters on the detection capabilities of a 2.4 GHz Doppler radar used in non-contact heart rate monitoring systems. Four different types of patch antennas and array configurations were implemented on both the transmitter and receiver sides. Extensive experiments using a linear actuator were performed and several interesting and nontrivial results were reported. It is shown that using a linearly polarized single patch antenna at the transmitter and a circularly polarized antenna array at the receiver results in the highest signal quality and system performance. Proof-of-concept experiments on human subjects further validated the suggested results. It was also shown that using the recommended antenna arrangement will boost the heart rate detection accuracy of the radar by an average of 11%.