In that case, they can be directly integrated and connected with 50- ohm transmission lines and achieve close to maximum power transfer. For example, some transceivers and antennas are specifically designed with impedances of 50 ohms (resistive) at their inputs (or outputs). Maximum power transfer between a source and a load occurs when their resistances are the same, or for AC circuits, when their impedances are complex conjugates of one another. They can even damage the transceiver source if the reflected power is too high- – an extremely dangerous situation in high- power applications. These reflections result in dramatically reduced signal range, dropped data packets, and wasted battery life. Impedance mismatches between an antenna and transceiver cause signal reflections at the feed point of the antenna, which are either absorbed back by the source or dissipated by lossy transmission lines and components. Two primary factors that reduce the signal power transferred between a source and load, such as in a transceiver and antenna system, are signal reflections and power dissipation losses. Why Impedance Matching is Important When Transmitting Power With the advent of portable USB-based VNAs, it's more affordable and convenient than ever to test and create your own antenna impedance matching network.
In this post, we’ll walk you through a straight-forward process for antenna matching with the TTR500 VNA.Ī similar process can be used for many other kinds of impedance matching needed to maximize power transfer between components in a system with high frequency signals or to check transmission line design or characteristic impedance.įigure 1. The Tektronix TTR500 vector network analyzer is a new affordable and easy- to- use option for performing antenna matching to improve the performance of wireless devices. Unfortunately, many engineers tasked with integrating an antenna into a wireless product have had limited or no access to a VNA due to the historically high cost of these instruments, or they have not been trained on how to use one. However, the best tool to make the impedance measurements needed to effectively design a matching network is a vector network analyzer (VNA). According to the inverse square law of radio waves, with only a 6dB improvement in path loss from improved matching, your device would transmit and receive at twice the range.Ī spectrum analyzer with tracking generator can check an antenna match by looking at the voltage standing wave ratio (VSWR). Properly matching an antenna to a transceiver is one of the easiest ways to extend the signal range and battery life of a wireless product, such as those made for the internet of things. How to Antenna Match with the Tektronix TTR500 in 5 Steps
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