RF Cafe - Waveguide Sizes Dimensions Formulas Equations

Waveguide & Flange Selection Guide

A few basic facts about waveguide:

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
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				f_{L -}f_U (GHz)	f_CO (GHz)	Inside Width (in)	Inside Height (in)
WR	U.S. Mil. __ /U	British Mil.	IEC	f_{L -}f_U (GHz)	f_CO (GHz)	Inside Width (in)	Inside Height (in)
WR975	RG204 (a)			0.75-1.12		9.750	4.875
WR770	RG205 (a)			0.96-1.45		7.700	3.850
WR650	RG69 (b) RG103 (a)	WG6		1.12-1.70		6.500	3.250
WR510				1.45-2.20		5.100	2.550
WR430	RG104 (b) RG105 (a)	WG8		1.70-2.60		4.300	2.150
WR340	RG112 (b) RG113 (a)	WG9A		2.20-3.30		3.400	1.700
WR284	RG48 (b) RG75 (a)	WG10		2.60-3.95	2.08	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-	3.156	1.872	0.872
WR159	RG343 (c) RG344 (a)	WG13	R58	4.90-7.05	3.705	1.590	0.795
WR137	RG50 (b) RG106 (a)	WG14	R70	5.850-8.200	4.285	1.372	0.622
WR112	RG51 (b) RG68 (a)	WG15	R84	7.050-10.000	5.26	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	7.847	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	11.54	0.510	0.255
WR42	RG53 (b) RG121 (a)	WG20		18.00-26.5	14.08	0.420	0.170
WR34	RG354 (c)			20.0-33.0	17.28	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		0.224	0.112
WR19		WG24		40.00-60.00		0.188	0.094
WR15	RG98 (s)	WG25		50.00-75.00		0.148	0.074
WR12	RG99 (s)	WG26		60.00-90.00		0.122	.061
WR10		WG27		75.00-110.0		0.100	0.050
WR8	RG138 (s)	WG28		90.00-140.0		0.080	0.040
WR7	RG136 (s)			110.0-170.0		0.065	0.0325
WR4	RG137			170.0-260.0		0.043	0.0215
WR3	RG139 (s)			220.0-325.0		0.0340	0.0170

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		f_{L -}f_U (GHz)	f_CO (GHz)	Maximum Inside Width (in)	Maximum Inside Height (in)
WRD	U.S. Mil. MIL-W-23351-	f_{L -}f_U (GHz)	f_CO (GHz)	Maximum Inside Width (in)	Maximum Inside Height (in)
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

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 Cover Grooved	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.