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# Waveguide & Flange Selection Guide

A few basic facts about waveguide: Here are Waveguide Equations & Fields

• The "WR" designation stands for "waveguide, rectangular"
• The wide inside dimension in inches is the "xxx" part of WRxxx; ie, WR650 is 6.50 inches, WR90 is 0.90 inches.
• The TE10 mode of propagation is the lowest mode that is supported.
• The waveguide width determines the lower cutoff frequency and is equal (ideally) to ½ wavelength of the lower cutoff frequency.
• The TE20, occurs when the width equals one wavelength of the lower cutoff frequency, and so on for higher modes.
• The TE01 mode occurs when the height equals ½ wavelength of the cutoff frequency, and so on to higher modes.
 H-Bend E-Bend An H-Bend is bent in the Hard direction (along the long side). This is the direction of the H-field in the TE10 mode. An E-Bend is bent in the Easy direction (along the short side). This is the direction of the E-field in the TE10 mode.
 Standard Rectangular Waveguide Click here for handy free "ezGuide" waveguide selector software from Andrew.
 Designation(a)=aluminum, (b)=brass, (c)=copper, (s)=silver fL - fU*(GHz) fCO**(GHz) InsideWidth(in) InsideHeight(in) WR U.S. Mil.__ /U BritishMil. IEC WR975 RG204 (a) 0.75-1.12 0.605 9.750 4.875 WR770 RG205 (a) 0.96-1.45 0.766 7.700 3.850 WR650 RG69 (b)RG103 (a) WG6 1.12-1.70 0.908 6.500 3.250 WR510 1.45-2.20 1.157 5.100 2.550 WR430 RG104 (b)RG105 (a) WG8 1.70-2.60 1.372 4.300 2.150 WR340 RG112 (b)RG113 (a) WG9A 2.20-3.30 1.736 3.400 1.700 WR284 RG48 (b)RG75 (a) WG10 2.60-3.95 2.078 2.840 1.340 WR229 RG340 (c)RG341 (a) WG11A R40 3.30-4.90 2.577 2.290 1.145 WR187 RG49 (b)RG95 (a) WG12 R48 3.95-5.85- 3.152 1.872 0.872 WR159 RG343 (c)RG344 (a) WG13 R58 4.90-7.05 3.712 1.590 0.795 WR137 RG50 (b)RG106 (a) WG14 R70 5.850-8.200 4.301 1.372 0.622 WR112 RG51 (b)RG68 (a) WG15 R84 7.050-10.000 5.260 1.122 0.497 WR90 RG52 (b)RG67 (a) WG16 R100 8.20-12.40 6.56 0.900 0.400 WR75 RG346 (c)RG347 (a) WG17 10.0-15.0 7.87 0.750 0.375 WR62 RG91 (b)RG349 (a) WG18 12.40-18.00 9.49 0.622 0.311 WR51 RG352 (c)RG351 (a) WG19 15.00-22.00 11.6 0.510 0.255 WR42 RG53 (b)RG121 (a) WG20 18.00-26.5 14.1 0.420 0.170 WR34 RG354 (c) 20.0-33.0 17.4 0.340 0.170 WR28 RG96 (s)RG271 (c) WG22 26.50-40.00 21.1 0.280 0.140 WR22 RG97 (s) WG23 33.00-50.00 26.4 0.224 0.112 WR19 WG24 40.00-60.00 31.4 0.188 0.0940 WR15 RG98 (s) WG25 50.00-75.00 39.9 0.148 0.0740 WR12 RG99 (s) WG26 60.00-90.00 48.4 0.122 0.0610 WR10 WG27 75.00-110.0 59.0 0.100 0.0500 WR8 RG138 (s) WG28 90.00-140.0 73.8 0.0800 0.0400 WR7 RG136 (s) 110.0-170.0 90.8 0.0650 0.0325 WR4 RG137 170.0-260.0 137 0.0430 0.0215 WR3 RG139 (s) 220.0-325.0 174 0.0340 0.0170
 * Per standard manufacturer's specifications** Cutoff frequencies calculated per standard rectangular waveguide equation. Double-Ridge Waveguide Double-ridge waveguide provides a wider operational bandwidth at the cost of higher insertion loss and lower power handling. The "D" in WRD stands for double-ridge. D24 at the end means a bandwidth ration of 1.24:1, etc.
 Designation(a) = aluminum, (b) = brass, (c) = copper fL - fU(GHz) fCO(GHz) MaximumInsideWidth(in) MaximumInsideHeight(in) WRD U.S. Mil.MIL-W-23351- WRD250 - 2.60-7.80 2.093 1.655 0.715 WRD350  D24 4-029 (a)4-303 (b)4-031 (c) 3.50-8.20 2.915 1.480 0.688 WRD475  D24 4-033 (a)4-034 (b)4-035 (c) 4.75-11.0 3.961 1.090 0.506 WRD500  D36 2-025 (a)2-026 (b)2-027 (c) 5.00-18.00 4.222 0.752 0.323 WRD650 - 6.50-18.00 5.348 0.721 0.321 WRD750  D24 4-037 (a)4-038 (b)4-039 (c) 7.50-18.00 6.239 0.691 0.321 WRD110  D24 4-041 (a)4-042 (b)4-043 (c) 11.00-26.50 9.363 0.471 0.219 WRD180  D24 4-045 (a)4-046 (b)4-047 (c) 18.00-40.00 14.995 0.288 0.134

Waveguide Flanges

 North American Waveguide Flange Shapes IEC Waveguide Flange Shapes Contact Grooved CPR CMR CAR UDR UER Square Cover Round Cover CPR Grooved UBR UAR PDR Choke Square Cover Grooved Round CoverGrooved CBR PBR PAR

Flange Style Designations

• UG:   UG is the military standard MIL-DTL-3922 for a range of flange types.
• CMR:   CMR flanges are the miniature version of the Connector Pressurized Rectangular

(CPR) style flanges.

• CPRG:   Connector Pressurized Rectangular (CPR) refers to a range of commercial

rectangular flanges. CPRG is Grooved CPR flange.

• CPRF:   Connector Pressurized Rectangular (CPR) refers to a range of commercial

rectangular flanges. CPRF is flat CPR flange.

• Cover or Plate:   Square, flat UG style flanges.
• Choke:   UG style flanges with an o-ring groove and a choke cavity.

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