Electronics Production | December 15, 2010
Ceramic chip antennas vs. PCB trace antennas: a comparison
Multi-purpose machine-to-machine devices require a high quality radio interface that will operate in the Zigbee, ISM, and cellular bands including LTE, bands which lie between 700 and 2500 MHz.
A trace antenna on a printed circuit board (PCB) is often the first type of interface considered for one of these applications. However, using a ceramic antenna can be a good or even better alternative. The purpose of a trace antenna on a PCB is to provide a method of wireless communication. During the manufacture of the PCB, the trace is laminated on the PCB’s surface or, in some cases, the traces can occupy several layers of a multilayer board. In these cases, vias are used to interconnect the traces on each layer. Feeding the antenna is normally arranged with a micro-strip line from the radio module. Using a trace antenna has several advantages: • Manufacturing costs are relatively low as the trace is applied as part of the PCB assembly process. • The structure is extremely simple and, because the antenna is on the surface of the PCB, the structure profile is very thin. • Optimally designed trace antennas have a large bandwidth. • They’re a good solution for sized-optomized PCBs in a stable environment. Some of the disadvantages are that trace solutions do not work well if: • The available PCB area for the antenna is small. • Objects are too close to the antenna area on the PCB. • They come in contact with, or are in close proximity to, people • The antenna performance and tuning are significantly affected by the PCB design. Because of this, the tuning needs to be checked/adjusted after each change made to the PCB layout. ------------------- About the Author Jouni Lifländer, RF designer for Pulse Finland Oy, has worked at Pulse Kempele since 2008. He has a Bachelor of Engineering from Rovaniemi Polytechnic and a Masters in Engineering, specializing in radio engineering, from the University of Oulu in Finland.