A Patch Antenna with Level-Controllable PIM Source

Intermdoulation in passive devices is known as Passive intermodulation (PIM). It often becomes a serious interfere especially in base-station antennas in a mobile wireless communication system. In antenna PIM measurement, it is difficult to distinguish the self-PIM from the one from other surrounding PIM sources [1] [2]. Although standard PIM generator is attractive to solve this kind of problem, it is also difficult to realize it as an antenna because the operating frequency of an antenna depends on its application. Therefore it is useful if a standard antenna that can generate fixed PIM level and control the generated PIM level. It would be effective to assess the quality of a measurement environment. In this paper, an antenna with level-controllable PIM sources is discussed. Through several experiments on a patch antenna, we propose several methods to control the generated PIM level. Specifically, we confirm the validity of a circular patch antenna with a diode-loaded parasitic element, and achieve the maximum controllable PIM-range of 55dB for 43dBm excitation.