Help on getting antenna measurements

Hi.

Its been a long time i try to design a antenna. I´m trying to build a circular slotted antenna for 2.44Ghz based on the paper "On the Miniaturazation of Cylindrical Omnidirectional Slotted WaveguideAntennas for Wireless Applications"

According to a paper:
1) It uses a C22 waveguide.
97.87mm in diameter.

2) Lenght: "5 * guides wavelength".
5 * 181.5mm = 907.5mm

3) Space between slots is "half guides´s wavelength".
181.5mm / 2 = 90.75mm

4) Slots are spaced 2º from the centerline.
?

5) Slots length: 0.55λ0.
181.5 * 0.55 = 99.825mm

6) Slots width: 3.3% of slots length.
3.29mm

7) Probe at "quarter guide´s wavelength".
45.4mm

8) Antenna top reflector at 0.365λ0 from the last slot.
181.5 * 0.365 = 66.248mm


Are my calculations correct? I´m a bit confused between "guides wavelenght"..

What does mean 4) ?

Also in the paper i didint find any reference the distance between the probe and the first slot..

A image of the antenna is attached (got it from Google Images).

Thanks.

4 ) could mean radial offset of slots. If yo look at the picture - slots are not in line - one to the left, next t the right and so on. I imagine center line is drawn and slots offset from it 2deg each way.
I think it is, can not say 100%.

Thanks for the answer.

That makes sense, rectangular slotted waveguides have a offset from the center.


My big confusion is regarding "half guides´s wavelength" and λ0:

Guides wavelenght for a diameter 97.87mm at 2.44Ghz is 181.9, so half guides wavelenght is 181.9/2..?

λ0 is wavelenght in free space, for 2.44Ghz is 122.87, so 0.55λ0, is 0.55*122.87..?

@fiwi thats for rectangular waveguides , i´m looking for circular waveguides. I tried simulate that measurements in a circular waveguide and it does not work great..

nadabro said:

@fiwi thats for rectangular waveguides , i´m looking for circular waveguides. I tried simulate that measurements in a circular waveguide and it does not work great..

Click to expand...

Well, then do a combination with this....https://www.changpuak.ch/electronics/cantenna.php

- - - Updated - - -

So it should look ..

nadabro said:

@fiwi thats for rectangular waveguides , i´m looking for circular waveguides. I tried simulate that measurements in a circular waveguide and it does not work great..

Click to expand...

...to remember.

Thanks for the schematic @fiwi.

Unfortunately according to a rude simulation i made (cant confirm or not), that schematic will not work well. The formulas that calculators provides maybe not work in a circular waveguide?

Anyhow, the schematic on rectangular waveguides is a bit different on the circular waveguide in image attached, particularly on the distance between probe and 1st slot.

nadabro said:

Thanks for the schematic @fiwi.

Unfortunately according to a rude simulation i made (cant confirm or not), that schematic will not work well. The formulas that calculators provides maybe not work in a circular waveguide?

Anyhow, the schematic on rectangular waveguides is a bit different on the circular waveguide in image attached, particularly on the distance between probe and 1st slot.

Click to expand...

You can show any antenna simulation?