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HF · ANTENNAS · SIMULATION

Multiband HF Fan Dipole Antenna

This article describes the design and simulation of a multiband HF fan dipole antenna using MMANA-GAL software. The design covers the 10, 20, 40 and 80 m bands. The simulations focus on determining the antenna's impedance and radiation patterns in each band.

HF · MULTIBAND DIPOLEMMANA-GAL
Multiband HF Fan Dipole Antenna

Warning: This model is provisional and is still being revised. The results may be inaccurate or contain errors.

Multiple dipole antenna
TypeMultiple dipole
DesignREMER
ImpedanceVariable
SimulationMMANA-GAL
BandMultiband
Remarks: Designed for the 10, 20, 40 and 80 m bands.
Download simulation fileBigote_gato_80-40-20-10m_Sim1.maa

1. Antenna design and modelling.

Multiple dipole antenna model in MMANA-GAL
Fig. 1. Multiple dipole antenna model in MMANA-GAL.

The antenna consists of several half-wave dipoles, each cut to a length corresponding to one of the operating bands. The operating bands in this design are 10, 20, 40 and 80 m. The arms of the dipoles on each side are connected together at a common feed point.

2. Simulation results.

This section presents the MMANA-GAL simulation results, including the calculated standing-wave ratios (SWR) and radiation patterns for each band.

2.1 Standing wave ratios (SWR).

The SWR values are calculated for a transmission-line characteristic impedance of 75 Ω. Achieving resonance on every band may be difficult, so it is recommended to use an antenna tuner. A suitable transmission line is 75 Ω twin-lead cable, although 50 Ω or 75 Ω coaxial cable may also be used.

Figures 2–5 show, respectively, the standing wave ratios calculated for the 10 m, 20 m, 40 m and 80 m bands.

SWR in the 10 m band
Fig. 2. SWR (75 Ω) in the 10 m band.
SWR in the 20 m band
Fig. 3. SWR (75 Ω) in the 20 m band.
SWR in the 40 m band
Fig. 4. SWR (75 Ω) in the 40 m band.
SWR in the 80 m band
Fig. 5. SWR (75 Ω) in the 80 m band.

2.2 Radiation patterns.

  • 10 m band: the radiation pattern is mainly bidirectional, with two main lobes along the antenna axis and several secondary perpendicular lobes. The simulated gain is approximately 7 dBi (Fig. 6).
Radiation pattern in the 10 m band
Fig. 6. Radiation pattern for the 10 m band.
  • 20 m band: the radiation pattern is bidirectional, with its main lobes along the antenna axis and a simulated gain of approximately 3 dBi. The main lobes have an elevation angle of approximately 50° (Fig. 7).
Radiation pattern in the 20 m band
Fig. 7. Radiation pattern for the 20 m band.
  • 40 m band: the radiation pattern is weakly bidirectional, with its main lobes perpendicular to the antenna axis. The simulated gain is approximately 5.2 dBi. The radiation pattern is suitable for NVIS propagation (Fig. 8).
Radiation pattern in the 40 m band
Fig. 8. Radiation pattern for the 40 m band.
  • 80 m band: the radiation pattern is approximately omnidirectional, with a simulated gain exceeding 5.5 dBi. The radiation pattern is suitable for NVIS propagation (Fig. 9).
Radiation pattern in the 80 m band
Fig. 9. Radiation pattern for the 80 m band.
ORIGINAL PUBLICATIONOCTOBER 2008