Provides a few information about the Ridge Guide, which is a type of an antenna used to overcome the disadvantages of Horn Antenna.

1. Ridge Guide
P.Maria Sheeba
I Yr M.E Communication Systems

2. Wave Guides
• Hollow conductors which are rectangular or
circular.
• Propagate electromagnetic energy above
certain frequency (cut off).
• Infinite number of modes can propagate, either
te or tm modes.
• When operating in a single mode, waveguide
can be described as a transmission line with
impedance zc & propagation constant g.

3. ENEE482 3
Rectangular
guide
Circular
guide
Ridge guide
Common Hollow-pipe
waveguides

4. Ridge Wave Guide Horns

5. Drawbacks of Horn Antenna
 In wideband testing systems,
applications of conventional horn
antennas become more and more
limited.
 While acting like band-pass filters,
horn antennas have limited bandwidth.

6. Contd...
 Hence, methods for broadening
antennas' widest working frequency
band are in urgent need.
 Ridged waveguides came to use in
the 1960s .

7. What is it??
 They are broadband radiators that are
used widely as standard gain horns for
calibrated gain measurements as well as
feed element in satellite tracking or
communication system.
 Ridges are used to increase the
bandwidth of regular horns.

8. What it does??
 A central ridge loads a waveguide and
increases its bandwidth by lowering
the cut off frequency of the dominant
mode.
 That is the fins OR ridge lowers the
cutoff frequency& increases the
antenna's bandwidth.

9. Uses & type of polarization :
 Dual ridge horns are used for gain
reference, as wideband probes for far-
field test ranges and as reflectors feeds
for high gain applications.
 Dual ridge horn produce linear
polarization.
 Quad ridge horn produces circular
polarization.

10.  Features:
 Linear polarized with
high polarization
 Low return loss/
VSWR
 Low weight
 High power

11. Problem in Ridge guide:
Radiation pattern distortion
arises in the high frequency band in
conventional ridged horn antennas,
caused by greater phase error at the
antenna aperture when the frequency
gets higher.

12. DRGH:
 Double Ridged Guide Horn Antenna.
 A novel ridge structure with slot loading
on ridges.
 The impedance matching characteristic
of the antenna in the lower frequency
band is improved greatly due to the
addition of the slot loading.

13. Side View of Antenna

14. Equivalent lumped circuit:

15. Parameters
 The total capacitance per unit length
C(F/m),
 The total inductance per unit length
L (H/m),

16. Cross-Sectional View

17. Other Parameters
The cutoff wavelength ratio in
waveguides with and without
ridges

18. The cutoff frequency of
rectangular ridged
waveguides is:

19. The characteristic impedance of
the dominant mode can be
calculated as follow when the
frequency is infnite:

20. Characteristic impedance
corresponding to finite
frequency f can be calculated
as:

21. Characteristic impedance and
cutoff wavelength of ridge wave
guide (b1/a1 = 0.35).

22. Specifications:
 Frequency Range (calibrated): 1–18
GHz
 Impedance: 50 Ohms nominal
 Average VSWR: <1.5:1
 Average Power Gain: 10.7 dB
 Average Beamwidth
E Plane: 53º
H Plane: 48º

23. Antenna Installation

24. Applications:
 It is a linearly polarized antenna capable of
operating as either a transmitting or receiving
antenna.
 Exhibits highly efficient performance
characteristics for a broadband antenna.
 It is also well suited for radiated susceptibility
testing in the microwave range and general
transmitting and receiving applications.

25. Thank You...