A device structure includes a first series connection of a first phase change memory (PCM) switch and a second PCM switch. The first PCM switch includes a first heater line, a first PCM line, and a first contact electrode and a second contact electrode located on the first heater line. The second PCM switch includes a second heater line, a second PCM line, and a third contact electrode and a fourth contact electrode located on the second heater line. The second contact electrode is electrically connected to the third contact electrode. The fourth contact electrode is electrically grounded. One of the first contact electrode and the second contact electrode includes an radio-frequency (RF) signal input port. Another of the first contact electrode and the second contact electrode comprises an RF signal output port. The device structure may function as a combination PCM switch that decreases noise level during signal transmission.