1/4 wavelength vertical monopole
MMANA-GAL simulation of a 1/4 wavelenght monopole designed for a central frequency of 146 MHz. The following results are shown: standing wave ratio, radiation pattern and antenna input impedance.
Article first published on 10/12/2009.
|Impedance: 58 + j17|
|Simulation: MMANA-GAL||Band: 2 meters|
Remarks: 4 radials layout at 45 degrees. Simulation at 7 meters over perfect ground.
1. Antenna design.
Fig.1. 1/4 wavelength monopole(Vademecum REMER)
Fig.2. 1/4 wavelength monopole modeled in MMANA-GAL
VHF - Dipolo L4 146 MHz radiales a 45º.maa
Simulation report (Z, SWR, Gain):
The antenna is made of a quarter-wavelength monopole for 146 MHz, plus a ground plane made of 4 radials separated 90 degrees between them and bent 45 degrees from the monopole.
2. Standing wave ratio (SWR).
Fig.3. SWR of the monopole simulated in MMANA-GAL
The fig.3 shows a plot of the SWR for a characteristic impedance of 50 ohms. The SWR at the central frequency (146 MHz) is 1,4.
3. Radiation pattern.
Fig.4. Radiation pattern of the monopole simulated in MMANA-GAL
The fig.4 shows the radiation pattern resulting from the simulation. The antenna is omnidirectional with a gain of 7,91 dBi.
4. Input impedance.
Fig.5. Input impedance of the monopole simulated in MMANA-GAL
The fig.5 shows the input impedance of the antenna, computed with MMANA-GAL between 144 MHz and 148 MHz. The input antenna impedance at the central frequency (146 MHz) is 58 + j17 ohms.
Ismael Pellejero - EA4FSI
VHF/UHF Antennas TOC