Normalized Impedance Normalized Z Actual Z / System Z0 For Z050, divide values by 50 Example: 37+55 37 55 50+ 50 0.74+1. Figure 18 shows how inductors and capacitors can be used to change the impedance. What is a Smith Chart A graphical tool to plot and compute: Complex impedance Complex reflection coefficient VSWR Transmission line effects Matching networks and more Let’s break it down. Capacitors and inductors in series or parallel can be used to match the antenna to the desired impedance. If varying these factors is not possible or if the performance still needs to be improved, discreet components could be used to optimize the impedance. Impedance matching o lumped elements o Single-stub matching o Quarter-wave impedance transformer.

Thus by varying these factors it might be possible to improve the impedance match of the antenna. Size of ground plane, distance from antenna to ground plane, dimensions of antenna elements, feed point, and plastic casing are factors that can affect the impedance. Dependent of the antenna type there are several possibilities to obtain optimum impedance at the correct frequency. If the resonance frequency is too high, the antenna length should be increased.Įven if the antenna resonates at the correct frequency it might not be well matched to the correct impedance. Thus if the resonance frequency is to low, the antenna should be made shorter. Ideally the frequency which gives least reflection should be in the middle of the frequency band of interest. For resonant antennas the main factor is the length. Impedance Smith Chart The Impedance smith charts are usually referred to as the normal smith charts since they relate with impedance and works really well with loads made up of series components, which are usually the main elements in impedance matching and other related RF engineering tasks. This is achieved by designing a matching network, or circuit between the feed line and the antenna. There are several ways to tune an antenna to achieve better performance. Smith chart can be used to perform an impedance match by bringing impedance to the center of the chart, which corresponds to a pure resistance of 50 by adjusting the reactance values. especially built-in antennas, such as spring type, chip type, pcb or fpc type antenna. To be precise, all antennas need impedance matching when applied to products. Antenna Matching is very important work in client side, not only antenna supplier side.

Smith chart matching