SEMCAD X
applications.jpg
Folded Monopole Antenna

The antenna and a pen nib


PCB mounting in the SEMCAD X model


E-field at 900 MHz

S11 Antenna
S11 for the antenna: unmatched (red) and matched (green)

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FOLDED MONOPOLE ANTENNA

 

Model

This electrically small antenna adopts a folded monople configuration, reducing the total volume to only 6x28x5 mm (operating at 900 MHz), which is constructed from stripline. In this application the antenna is mounted onto a PCB with a truncated ground plane. The antenna is fed with a 50 Ohm stripline, a 3 element T matching network is used to match the antenna input to that of the feedline.

Simulation

The stripline antenna parts are resolved using 3-5 cells across their width and the thickness of the subtrate is resolved with 5 cells to ensure the performance is correctly represented. The C and L matching network components are designed based on the unmatched simulated Zin of the antenna in order to match it to 50 Ohm at 900 Mhz. Both harmonic and transient simulations are run centered around 900MHz.

Results

The performance of the matching network shows a slight (1.3%) shift in the center frequency, which would require further tuning. However the S11 shows substantial improvement from -0.4 dB (unmatched) to -16.5 dB (matched). The far-field is recorded and is similar to a standard monopole antenna.

 

 

created and designed by R.Ø.S.A.