Design of Broadband double ridge Horn Antenna
Can any one help me out in designing of Broadband Double Ridged Horn antenna. I have thoroughly gone through the below IEEE papers. There are some doubts arising for me to proceed further on designing.
- Does we need to plot the curves (S/A vs λ/A); or else use the readily available curves.
- What should be the mode of propagation to be selected [TE10 or TE20 or TE30].
- What are the wave guide dimensions to be selected ? What are the conditions to select the wave guide dimensions ?
- How the height of the ridge is to be varied in the flared section ? Does it follow any equation.
- What should be the total length of the Horn Antenna ? If so what is the reason for selecting that length ?
Walton, K. L. and V. C. Sundberg, ?Broadband ridged horn design,? Microwave J., 96?101, March 1964.
Cohn, S. B., ?Properties of ridged waveguide,? Proc. IRE, Vol. 35, 783?788, Aug. 1947.
Hopfer, S., ?The design of ridged waveguides,? IRE Trans. Microwave Theory Tech., Vol. MIT-3, 20?29, October 1955.
All antennas are scaleable with frequency. You start with frequency range you need. First dimensions you want to determine - waveguide dimensions. It follows from your required frequency range and from equipment you will be using it with, if you use waveguide port.
Hi Andrey,
Thanks for your response.
The design of double ridge Horn antenna slightly varies from the standard horn antenna. As there are ridges in the waveguide section and flare section of horn, the discontinuity susceptance comes into picture, and these impendances, depends upon the width, gap between the ridges, and these parameters must be consider while determining the waveguide dimensions.
My pleasure. You certainly know more about double-ridged horn design than I do. Yet i believe my advice holds: define frequency range, determine the wave guide you need (standard size I assume). After that, if you do not find the answers to all your delicate questions, take dimensions from the papers you listed and scale it to your frequency range. Then you build prototype or model it if you got the software. Measure and study your model. And you find answers to your questions yourself.
Good luck!
BTW how adding ridges to the horn makes it better? Polarization purity?
Hi All,
I have simulated the ridge horn antenna (1-18 GHz) in HFSS, with 9 GHz as central frequency with coaxial probe as excitation.
The simulated results show S11 as -12.5551 dB at 9 GHz, whereas it is not in the acceptable level (more than -10 dB) in the rest of the frequency ranges except at frequencies beyond 12 Ghz.
Whether the antenna is good to go for fabrication, as the antenna gain is more than 7.5 dB over the entire band of frequency, if not what are all the changes required on antenna structure.
all I know is, the tiny area where you transition from coax to ridge is VERY important.
I used to make horns many years back; without the ridge; I got return loss -15dB or better across design frequency band. Maybe worth building prototype and see how it compares with simulation.
What I remember is, wave guide also plays important role in this design ( including ridge thickness & height).
Distance of probe from bottom,impedance plays crucial role.
Remember one thing, you are transferring impedance from 377 ohm to say 50 ohm.
so this transition should happen smoothly. Curvature of ridge is extremely important.
What I recommend is, check your design step by step, check if your waveguide is exiting correct modes.
then you go for ridge & horn body construction in HFSS.
Do literature study.
Lot of material is available on internet on this topic.
For information you can check antenna made by Lindgren-ETS. It will be good benchmark.
Hi Abhishek,
Upon extensive search on the internet, the ridge horn antenna, which was simulated is of the standard dimensions of the ridge horn antenna.
As per the technical literature, it mentions that the co-axial probe should pass through the top ridge and should short the opposite ridge through metal conductor of the probe and same has been implemented in the structure.
And for transferring of the probe impedance (50Ω) to free space impedance (377Ω) exponential tapering was used. But the simulated results does not giving a good S11 plot over the entire band.
Can you once look over the drawn structure and help me out wht are all the changes required for improving the S11.
PFA for the .hfss file RidgeHornCoaxial Probe.rar