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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.
  • Click here for waveguide formulas.
H-Bend E-Bend
Waveguide equation formula drawing fields - RF Cafe

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.

Waveguide equation formula drawing fields - RF Cafe

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.


(a)=aluminum, (b)=brass, (c)=copper, (s)=silver

fL - fU*










WR U.S. Mil.

__ /U



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.


(a) = aluminum, (b) = brass, (c) = copper

fL - fU












WRD U.S. Mil.


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 Waveguide - RF Cafe

Contact Grooved

CPR Waveguide - RF Cafe


CMR Waveguide - RF Cafe


CAR Waveguide - RF Cafe


UDR Waveguide - RF Cafe


UER Waveguide - RF Cafe


Square Cover Waveguide - RF Cafe

Square Cover

Round Cover Waveguide - RF Cafe

Round Cover

CPR Grooved Waveguide - RF Cafe

CPR Grooved

UBR Waveguide - RF Cafe


UAR Waveguide - RF Cafe


PDR Waveguide - RF Cafe


Choke Waveguide - RF Cafe


Square Cover Groved Waveguide - RF Cafe

Square Cover


Round Cover Grooved Waveguide - RF Cafe

Round Cover


CBR Waveguide - RF Cafe


PBR Waveguide - RF Cafe


PAR Waveguide - RF Cafe


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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