Does Antenna Optimization Really Make It Or Break It?

At Abracon, we get this question a lot. The Internet of Things has awakened a renaissance in connectivity, both wired and wireless. The wireless aspect in particular is experiencing explosive growth.

With the emergence of 5G, practically every place on the planet will have a wireless connection. Protocols such as LoRa and Sigfox appeared on the horizon specifically to address IoT requirements of power, cost and deployment. Since almost everyone carries a cell phone, Bluetooth capability means a device can become an extension of a deployed mobile phone for consumer and commercial applications alike and WiFi brings networking and broadband. Finally, geolocation and tracking applications enable any device to find itself, anywhere on the planet through GNSS or RFID access.

What is the common denominator in these designs? RF connectivity always requires an antenna. Moreover, there is constant pressure to extend battery life while increasing range and sometimes data rate. In the critical path of the RF signal, the antenna all too often becomes a chokepoint for the signal, reducing RF reception and transmission efficiency. This causes peak gain mismatch or detuning, which degrades the link budget, a reduced RF sensitivity and a lower RF coupling from the transmitter into the air. In particular, chip antennas designed for IoT applications must avoid these conditions.

Something has to give as the coupling to the antenna becomes less efficient. Your design may compensate by boosting RF transmission power levels. This has a direct impact on battery life. Also, your bit error rate may increase, causing more resends of data and keeping the device active longer. Again, this impacts battery life. Another factor is poor reception. Lower than optimal reception hurts receive range which is quite noticeable by the end user. In the case of detuned patch antennas, there may be increased interference with transmission and reception occurring in unintended bands.

If two products are tested side by side, the user will likely choose the one with the most range and most robust connectivity.

So is it important to tune patch antennas and match chip antennas to the RF signal chain? You bet it is, and in fact, it may make or break your product. Chip antennas are optimized using external matching networks such as an L, pi or a “T” configuration. The network matches the complex impedance of the RF chain at the antenna input to 50 Ohms. Patch antennas are tuned differently. Rather than adjusting L and C components on the PCB, patch antennas are tuned by trimming small amounts of metal off the antenna. The metal is trimmed until the antenna and ground plane are centered on frequency and the gain is maximized to achieve top efficiency.

Testing and tuning the antenna requires costly RF equipment such as vector network analyzers and RF sources. A reality of IoT is that many design teams may be involved with RF design for the first time. In these cases, the teams may not have access to the equipment or they may be focusing on other parts of the design. Outsourcing these tests is possible. As a supplier, Abracon offers antenna optimization services for both patch and chip antennas.

To conclude, the antenna is in the critical path of signal reception so its efficiency is a make or break it parameter. There is no reason to leave the antenna design up to chance when it could affect other major design objectives such as battery life, range, data rate and end user satisfaction. The following article shows a step by step approach to chip antenna matching. Following these steps will help optimize the design and achieve your major product objectives. If you lack the equipment, just call Abracon.

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