Several factors may affect the fine-tuning process of the antenna: Orientation of the antenna. Impedance matching of the antenna and the micro-strip line. Length of the micro-strip feed line on the no-ground plane. If the length is not kept at minimal, the feed line may act as a parasitic radiating antenna. PCB layout: taken into account the ground plane, metal layers, and adjacent surface mount components. Housing material over the antenna may also impact the antenna performance. Adjacent metal devices placed near the antenna, such as batteries, speakers, LCD panels. Impedance matching with capacitors and/or inductors, which will be discussed in the next slide.