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4 Ways To Match Antenna Debug
Source:Original | Author:Calio Huang of C&T RF Antennas Inc | Publish time: 2019-07-21 | 1005 Views | Share:

Usually, the impedance matching at a certain frequency point can be performed by the SMITH chart tool. The two devices can definitely do the same, that is, the impedance matching from any point on the chart to another point can be realized by the string + shunt inductor or capacitor, but this It is single frequency. The mobile phone antenna is dual-frequency, and matching one of the frequency points will inevitably affect another frequency point, so the impedance matching can only be compromised in two frequency bands.

Matching at a certain frequency is easy, but the dual-frequency is more complicated. Because the 900M is completely matched, then 1800 will not reach the match, it is a suitable matching circuit. It is best to use simulation software or a point matching, and adjust it under the S11 parameter on the network analyzer because the matching point of the dual-frequency is definitely not too far from here, only the two components match is unique, but the pi type There are countless solutions to network matching. At this time, you need to simulate to pick, it is best to use experience.

Simulation tools are almost useless in the real world. Because the simulation tool is not aware of the model of your component. You have to enter the model of the actual component, that is, the various distribution parameters and your results may match the actual. An actual inductor is not simply measured by the amount of inductance, it should be an equivalent network to simulate.

In the actual design, you should fully understand the principle of the Smith chart, and then use the network analyzer's circle chart tool to debug more. Knowing the principle allows you to know exactly what to use. Multi-tone is to let you know how the components you use will move on the actual circle. (Because of the distribution parameters and the frequency response characteristics of the components, the movement of the actual part on the chart and the movement of your theoretical calculation will be different).

Dual-frequency matching is indeed a compromise process. You must add one piece to be purposeful. In the case of GSM and DCS dual-band, if you want to adjust GSM and don't want to change DCS, you should choose the way of a series capacitor and shunt inductor. Similarly, if you want to adjust the DCS, you should choose the string inductor and capacitor.