The PCB trace length will determine the resonant frequency; the higher the frequency the shorter the trace. Each antenna requires a keep out area on the PCB. This is defined as an area around the antenna trace where no copper traces or ground fill can be used on any layer of the PCB. Wider traces are often better, as they typically give a wider bandwidth. The trace can either be gold flashed or covered with solder mask. The antenna’s electrical performance will be determined by the substrate material used, its thickness, and dielectric constant (εR).