Parts List/Tune Up Info

Table Of Contents

2.3 Bandwidth

Another way of measuring the bandwidth after the antenna is implemented on a PCB and connected to a

transmitter is to write test software that steps a carrier across the frequency band of interest. By using the

maximum hold function on a spectrum analyzer, the variation in output power across frequency can easily be

measured.

Figure 2-9 shows how the output power varies on the IFA when the PCB is horizontally oriented and the

receiving antenna has horizontal polarization. This measurement was not performed in an anechoic chamber,

thus the graph shows only the relative variation for the given frequency band.

Figure 2-9. Bandwidth of IFA

3 Summary

The PCB antenna presented in this document performs well for all frequencies in the 2.4-GHz ISM band. Except

for two narrow dips, the antenna has an omni directional radiation pattern in the plane of the PCB. These

properties will ensure stable performance regardless of operating frequency and positioning of the antenna.

Table 3-1 lists the most important properties for the IFA.

Table 3-1. Summary of IFA Properties

Gain in XY plane 1.1 dBi

Gain in XZ plane 3.3 dBi

Gain in YZ plane 1.6 dBi

Reflection < –15 dB

Antenna size 25.7 × 7.5 mm

4 References

1. CC2430DB Reference Design

www.ti.com Measurement Results

SWRU120D – APRIL 2007 – REVISED JANUARY 2019

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2.4-GHz Inverted F Antenna 11