Antenna system with base configuration for passive inter-modulation (PIM) mitigation

An antenna system comprising:

• an antenna element configured to radiate signals, receive signals, or radiate and receive signals;
• a base plate having a front surface facing the antenna element and a rear surface facing away from the antenna element, the front surface of the base plate having an uncovered area, wherein the uncovered area of the base plate is planar having no protrusions;
• a ground plane having a front surface facing the antenna element and a rear surface facing away from the antenna element, the front surface of the ground plane having an uncovered area, wherein the uncovered area of the ground plane is planar having no protrusions;
• a capacitive coupling between the base plate and the ground plane formed by an overlap region between the base plate and ground plane, the ground plane capacitively coupled to the base plate in the overlap region, a capacitance created by the base plate and the ground plane within the overlap region being greater than a capacitance created by the base plate and the ground plane outside the overlap region;
• and
• mechanical joints mounted from a rear side of the antenna system, the mechanical joints not viewable from a front side of the antenna system.