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# Aperture Antennas

Rectangular Horn Antenna

# Rectangular Horn Antenna

Rectangular horn antenna is one of the simplest and most widely used antennas. Horns have been used for more than a hundred years, and today they used in radio astronomy, satellite communications, in communication dishes as feeders, in measurements, etc.

The main characteristic of the rectangular horn antenna presented here is its approximately 20 dB gain. Horn antenna can be considered as an especially designed waveguide extension. The most important parameters for operation of this antenna are shown in Fig. 1. These parameters are:

• Length of antenna (determined by Lhorn)
• Width of aperture (determined by a2 and b2)

Figure 1. Rectangular horn

Figure 2. Quarter of a rectangular horn

## WIPL-D Simulation

Table 1. Parameters of analysis

Parameter Value [mm]
a2 123.7
b2 91.95
Lhorn 255.5

Table 2. Simulation data

Model No. of unknowns Memory [MB] Time @ 10GHz [sec]
quarter 658 3.3 0.56
half 1266 12.2 0.75
full 2478 46.8 1.69

In WIPL-D Pro, horn antenna given in Fig. 1, can be modeled in a very simple way, by using several basic building blocks. One can use the Symmetry feature in both electric and magnetic plane, so only half or quarter of given antenna can be modeled (Fig. 2), depending on the type of feeding. Antenna is considered to be surrounded by vacuum, i.e. it is located in free-space.

For parameters given in Tab. 1, we will calculate gain, near field and we will compare analysis characteristics for different models of antenna (with and without Symmetry feature). Computer used for these calculations is Intel® Core(TM) i7 CPU 950@3.07 GHz.

Dimensions of the rectangular horn model are given in Tab. 1. Operating frequency is 10 GHz.

Radiation pattern is shown in Fig. 3 and its phi-cut, where phi=0 (antenna is placed along x axis) is shown in Fig. 4. Please note that the theta angle is measured with respect to the xOy plane.

Calculated near field is shown in Fig. 5. It illustrates the radiation mechanism of the horn.

Numbers of unknowns, memory requirements, and simulation time are given in Tab. 2.

Figure 5. Near field

## Conclusion

The rectangular horn antenna is one of the simplest antennas for EM modeling and simulation. However, some simulation tools use computational methods that require relatively long time (several minutes) to produce results even for the simplest horn models. WIPL-D Pro provides simulation results swiftly in a matter of seconds rather than minutes, demonstrating that higher order MoM makes a difference comparing to other methods even on the simplest examples, not just the electrically large structures.

## PDF application note

If you have a specific problem in mind and you are not sure if WIPL-D software can handle that problem, contact us. We will analyze your needs and try to help, and if our products satisfy your requirements, we will make you the best possible offer for purchase.