Slotted Cylindrical Antenna Calculation
By: Onno W. Purbo YC0MLC
Frequency 2.437 GHz
D of your can 9.017 cm
N Slot 4
Wavelength 12.310 cm
D minimum 7.386 cm
D maximum 9.233 cm
Guiding Wavelength (Lg) 20.528 cm
¼ Lg 5.132 cm
½ Lg 10.264 cm
4.5 Lg 92.378 cm
¼ L (air) 3.078 cm
N Slot x ½ Lg 41.05670014 cm
N Slot x ½ Lg + ½Lg + ¼Lg 56.45296269 cm
n x Lg 61.58505021 cm
Waveguide Slot Antenna Calculator
updated 5/30/2002 W1GHZ 2000
Parameter Metric Inches Metric Inches
ENTER INPUT PARAMETERS HERE:
Frequency 2.437 GHz 2.437 GHz
Waveguide large dim 90.17 mm 0.9 inch
Waveguide small dim 86.7 mm 0.4 inch
Number of slots 4 16 total on two sides
Estimated Performance Gain = 4.4 dB Beamwidth= 37.1 deg
READ FINAL SLOT DIMENSIONS HERE:
old from KB7TRZ improved from Elliott
Offset from centerline 20.75 mm 0.817 inch 23.23 mm 0.915 inch
Length 61.55 mm 2.423 inch 60.89 mm 2.397 inch
Width 8.42 mm 0.332 inch 1.59 mm 0.063 inch
Slot spacing center to center 84.23 mm 3.316 inch 84.23 mm 3.316 inch
End space = 1/4 wave 42.11 mm 1.658 inch 42.11 mm 1.658 inch
End space = 3/4 wave 126.34 mm 4.974 inch 126.34 mm 4.974 inch
End space is from shorted end to center of last slot
Wavelength - free space 123.10 mm 4.847 inch
Wavelength - cutoff 180.34 mm 7.100 inch
Guide wavelength 168.45 mm 6.632 inch
INTERMEDIATE TERMS -- DON"T MESS WITH THESE!
Gslot 0.2500 0.2500 enter taper admittance here
G1 0.5010 0.4103
Y 0.4990 0.6093
Offset calculation: Mathcad from KB7TRZ: New offset calc from Elliott:
OFFSET 20.75 mm 0.817 inches 23.23 mm 0.915 inch
Offset calculation: BASIC from W6OYJ:
AG 0.52 mm
Offset 20.75 mm 0.817 inches
Slot Length Calculation from Stegen curves:
Slot in wavelengths 0.4946
Slot Length 60.89 mm 2.397 inch
