We designed and fabricated a microwave transmitting antenna that uses an HTS thick disk as a patch antenna with a resonant frequency of around 5.0 GHz. The reflection property S 11, electromagnetic fields, current distributions, and far-field of several resonant modes in the antenna were analyzed using the CST studio suite. We compared the properties in several resonance modes and selected the TM11 mode, which has the smallest resonator size and the highest directivity. The antenna was assembled using a GdBCO thick disk, sapphire substrates, Cu housing, and SMA connector. We measured the S 11 using a vector network analyzer and pulse tube refrigerator and found that it had a resonant frequency of 4.996 GHz and a Q u of 405 at the temperature of 48 K. These measured properties were in good agreement with the simulated results.