7-9.2 Satoh Horn

The Satoh horn uses a dielectric cone inserted into a smooth-wall conical horn which generates the TM11 mode.  The dielectric cone is placed so that corrugated performance is achieved.  CHAMP (TICRA) can be used to design this horn through optimization of the parameters: gain at center frequency, maximum cross-polarization, and return loss over a small frequency range.  The horn analysis uses an initial conical section from the waveguide to the dielectric cone solved by mode-matching.  The rest of the horn is analyzed using BOR-MoM and includes the dielectric cone , the cone to the aperture, and the external surface of the horn.  Figure 7-9.2-1 shows the location of the dielectric cone in the horn.

satoh1512
Figure 7-9.2-1 15 dB Gain Satoh Horn cross-section illustrating the dielectric cone (green) used to generate the TM11 mode
Table 7-9.2 lists parameters of Satoh horns designed by using the optimization of CHAMP.

Table 7-9.2 Parameters of Satoh Horns, using Teflon Cones


Gain
dB

Aperture Radius, λ

Slant
Length, λ

To Dielectric
Step, λ

Dielectric Thickness

Cone Length, λ

25-dB
X-pol BW, %

10 dB Beam-width

Phase Center, λ

15

1.0465

6.9983

0.8455

0.1640

0.9674

12.2

61.7

3.169

16

1.1550

6.2879

0.4650

0.1782

0.9439

11.4

56.1

3.269

17

1.3452

6.7636

0.4495

0.1825

0.9322

13.5

49.3

3.759

18

1.4606

8.8020

1.0936

0.1294

0.9732

19.8

43.4

4.610

19

1.6719

9.8613

1.2722

0.1344

0.9555

19.2

38.8

5.174

20

1.8134

10.335

1.0933

0.1089

1.4908

15.2

34.7

6.363

21

2.2153

11.392

1.0235

0.1364

0.9489

20.3

30.4

5.864

22

2.7976

13.028

0.9524

0.1503

0.9343

19.7

27.2

5.823

23

3.0384

15.687

1.4148

0.1432

0.9746

15.2

24.3

8.414

The Satoh horn when optimized using CHAMP has about twice the cross-polarization bandwidth compared to the Potter horn with its single metal step.

A longer report along with a CHAMP test input file can be downloaded Step_Multi-mode_horns.zip.
20_Gain_10 GHz
20 dB Gain Satoh Horn Center Frequency Response (10 GHz)

20_Gain_X-pol
20 dB Gain Satoh Horn Maximum Cross-polarization relative to Peak Response versus Frequency

37. T. Satoh, Dielectric Loaded Horn Antenna, IEEE Transactions on Antennas and Propagation,
vol. AP-20, no. 2, March 1972, pp. 199-201.