Effect of Ground Clearance Reduction in Chip Antenna for IoT Micro-PCBs

In order to find solutions for miniaturizing printed circuit board (PCB) area in products for the Internet of Things, a comparative study between different ground clearance sizes in a same chip antenna is presented. Two micro-PCBs intended for a Bluetooth Low Energy system-in-package have been designed, using the same commercially available microcontroller, transceiver, and chip antenna. On one board, the clearance area around the antenna followed the manufacturer's recommendations and, on the other, a non-copper area was left only immediately below the antenna. A development board has also been designed to compose a complete system. Measurements of received signal strength indicator, latency, and throughput have been taken in a controlled environment and in the field to evaluate the quality of the communication in both cases. Radiation patterns of both PCBs have also been plotted. The micro-PCB without ground clearance shows a surface saving of 12.23% and a suitable enough performance for short-range communications.