mw notions

Microwave notions (a few notes)

dBm, volts and watts conversion table:

dBm to Volts_(rms) to Watts – Conversion Table _{(50 Ohms)}

dBm	V	Po	dBm	V	Po	dBm	mV	Po	dBm	uV	Po
+53	100.0	200W	0	.225	1.0 mW	-49	0.80		-98	2.9
+50	70.7	100W	-1	.200	.80 mW	-50	0.71	.01 uW	-99	2.51
+49	64.0	80W	-2	.180	.64 mW	-51	0.64		-100	2.25	.1 pW
+48	58.0	64W	-3	.160	.50 mW	-52	0.57		-101	2.0
+47	50.0	50W	-4	.141	.40 mW	-53	0.50		-102	1.8
+46	44.5	40W	-5	.125	.32 mW	-54	0.45		-103	1.6
+45	40.0	32W	-6	.115	.25 mW	-55	0.40		-104	1.41
+44	32.5	25W	-7	.100	.20 mW	-56	0.351		-105	1.27
+43	32.0	20W	-8	.090	.16 mW	-57	0.32		-106	1.18
+42	28.0	16W	-9	.080	.125 mW	-58	0.286
+41	26.2	12.5W	-10	.071	.10 mW	-59	0.251		dBm	nV
+40	22.5	10W	-11	.064		-60	0.225	.001 uW	-107	1000
+39	20.0	8W	-12	.058		-61	0.200		-108	900
+38	18.0	6.4W	-13	.050		-62	0.180		-109	800
+37	16.0	5W	-14	.045		-63	0.160		-110	710	.01 pW
+36	14.1	4W	-13	.050		-64	0.141		-109	640
+35	12.5	3.2W	-16	.0355					-112	580
+34	11.5	2.5W				dBm	uV		-113	500
+33	10.0	2W	dBm	mV		-65	128		-114	450
+32	9.0	1.6W	-17	31.5		-66	115		-115	400
+31	8.0	1.25W	-18	28.5		-67	100		-116	355
+30	7.10	1.0W	-19	25.1		-68	90		-117	316
+29	6.40	800mW	-20	22.5	.01 mW	-69	80		-118	285
+28	5.80	640mW	-21	20.0		-70	71	.1nW	-119	251
+27	5.00	500mW	-22	17.9		-71	65		-120	225	.001 pW
+26	4.45	400mW	-23	15.9		-72	58		-121	200
+25	4.00	320mW	-24	14.1		-73	50		-122	180
+24	3.55	250mW	-25	12.8		-74	45		-123	160
+23	3.20	200mW	-26	11.5		-75	40		-124	141
+22	2.80	160mW	-27	10.0		-76	35		-125	128
+21	2.52	125mW	-28	8.9		-77	32		-126	117
+20	2.25	100mW	-29	8.0		-78	29		-127	100
+19	2.00	80 mW	-30	7.1	.001mW	-79	25		-128	90
+18	1.80	64 mW	-31	6.25		-80	22.5	.01 nW	-129	80	.1ƒW
+17	1.60	50 mW	-32	5.8		-81	20.0		-130	71
+16	1.41	40 mW	-33	5.0		-82	18.0		-131	61
+15	1.25	32 mW	-34	4.5		-83	16.0		-132	58
+14	1.15	25 mW	-35	4.0		-84	11.1		-133	50
+13	1.00	20 mW	-36	3.5		-85	12.9		-134	45
+12	.90	16 mW	-37	3.2		-86	11.5		-135	40
+11	.80	12.5mW	-38	2.85		-87	10.0		-136	35
+10	.71	10 mW	-39	2.5		-88	9.0		-137	33
+9	.64	8 mW	-40	2.25	.1uW	-89	8.0		-138	29
+8	.58	6.4 mW	-41	2.0		-90	7.1	.001 nW	-139	25
+7	.500	5 mW	-42	1.8		-91	6.1		-140	23	.01ƒW
+6	.445	4 mW	-43	1.6		-92	5.75
+5	.400	3.2 mW	-44	1.4		-93	5.0
+4	.355	2.5 mW	-45	1.25		-94	4.5
+3	.320	2.0 mW	-46	1.18		-95	4.0
+2	.280	1.6 mW	-47	1.00		-96	3.51
+1	.252	1.25 mW	-48	0.90		-97	3.2


	Relative measurements

	Relative measurements are defined in dB units and generally refer to transmission path losses ( Lossy transmission path )

	Microwave signals measured in watts:

		dB = 10 log ( P₁ / P₂ ) where P₁ = measured power level ( eg in Watts ) and P₂ = reference power level ( eg in Watts )

	Microwave signals measured in Volts:

		Electric signals are often measured in volts. However the electrical energy goes up with the square of the voltage. So when working in volts, the relationship is defined as: dB = 20 log ( P₁ / P₂ ) where P₁ = measured amplitude level ( eg in Volts ) and P₂ = reference amplitude level ( eg in Volts )