8) Changing VSWR with chip inductors

VSWR is tunable with 3 chip inductors.
We used our standard evalutaion board for this example. Chip inductors L1 and L2 are in series with the feed point and one of the terminals of the chip antenna and are used to adjust the resonance frequency. Chip inductor L3 is in parallel between the feed point and GND and is for impedance tuning.


・ Fig. 8-1 shows how changing L3 affects VSWR. Minimum peak frequency changes little and VSWR increases when changing L3 from the optimal value 27nH (Fig. 8-2.)
・ Fig.8-3 shows how changing L2 can shift the resonance frequency higher or lower without increasing minimum VSWR.
・ Fig.8-4 shows how L1 and L2 affects resonant frequency and it is reduced 0.76MHz as L3 is increased by 1nH.

 

 

 

 

 

 

 

 

 

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