Software-defined radio transmitters provide a rather unique opportunity when it comes to supplying a complete bits-to-antenna experience. This allows users to communicate with remote sensors as well as two-way systems, such as WiFi adapters and 5G modems. However, even the most sophisticated VPX SDR chip would struggle without the ability to tune its antenna system.
A group of specialists have found a way to match the impedance of transmission circuits in very small VPX SDR modules. Despite what many people believe, so-called antenna tuners don’t actually have inaccurate antennas so they can resonate on a frequency that they weren’t cut for. Rather, these devices match differing impedance measurements to reduce the presence of standing waves. Whenever a radio circuit transmits, such as when a digital radio sends out a packet, it could end up getting reflected as a result of slight irregularities.
Eventually, the amount of reflected power can start to build up in the transmission line until it starts to interfere with RF power coming from the transmitter. This can create standing waves, which require an impedance trans-match circuit to handle. Miniature antenna tuners alleviate this problem more than anything else, but that doesn’t mean that they’re not necessary. Engineers believe they might have solved many of these issues by using just a few simple parts and cutting antennas closer to their resonant frequencies.
Check out a full specifications sheet for a VPX SDR module by visiting online at Epiq Solutions.
