TRU Design Aids 1

Attenuation
CABLE/CONNECTOR DIELECTRIC MATERIALS
α�= ( k1 x √ f(MHz) + (k2 x f(MHz)) (dB/100ft)
Dielectric Constant
(Nominal)
Material
Wavelength
Temperature
Ranges (°C)
Air
1.00
Solid PTFE
2.10
-75 to +250
Low Density PTFE
1.60
-75 to +250
Cellular TFE
1.40
-75 to +250
PFA
2.10
-75 to +260
Characteristic Impedance
Flouroloy H.
2.43
-75 to +204
D
Zo = 60 x Vp x In ( d ) (ohms)
PE
2.30
-65 to +85
Foam PE
1.46
-95 to +100
Boron Nitride
4.00
-75 to +1800
11.8021 x Vp
λ=
(in)
f(GHz)
Length Given Delay
L = .9835 x T x Vp (ft)
Cut Off Frequency
fco = 7.51 x Vp (GHz)
D+d
d
D
TYPICAL AVERAGE POWER DERATING FACTORS
Temp °C
Derating
Factor
Altitude x
1000 ft
Derating
Factor
0
1.20
0
1.00
Phase Length
40
1.00
20
.80
φ = 30.5 x L(in) x f(GHz)
Vp
80
.80
30
.70
120
.60
40
.60
160
.40
50
.50
200
.20
60
.40
240
.05
70
.30
Time Delay
T = 1.016 (ns/ft)
Vp
Capacitance
C(pF/ft) =
16.97
Vp2 ln D
d
Velocity of Propagation
Vp =
1
√Er
TRU Corporation
245 Lynnfield Street, Peabody, MA 01960 1-800-COAX-TRU (1-800-262-9878)
www.trucorporation.com