RF CABLE
High Speed Extrusion of physically
foamed 50 Ω RF Cable
•
50 Ω RF Cable Products 1/4” – 1 5/8”
•
PE Materials and Additives
•
Physically Foaming Agents
•
SIEBE High Speed Line 5/8” – 2 ¼”
1. Product – 50 Ohm RF Cables
When it comes to connecting the mobile communication antenna with the base
station, 50Ω radio frequency cable, manufactured on SIEBE extrusion lines, are
the optimum antenna cable for the job. They offer excellent return loss and
extremly low attenuation due to a dielectric, that consists of highly foamed
Polyethylene.
Generally 50Ω radio frequency cables are constructed as follows:
• Inner conductor of bare copper wire, smooth copper tube or corrugated
copper tube
• Dielectric of highly foamed polyethylene
• Outer conductor of a corrugated copper tube with annular or spiral corrugation,
depending on the flexibility required
• External sheath of PE or FRNC
1. Product – 50Ω RF Cables ¼” – 2 1/4”
Cable
Conductor
Conductor
∅
Insulation
Insulation
∅
Capacitance
Impedance
¼“
Copper wire
1.90
SF (SFS)
PE
4.40
80
50
3/8“
Copper wire
2.60
SF (SFS)
PE
6.50
80
50
½“
Copper wire
3.55
SF (SFS)
PE
9.30
80
50
5/8“
Copper wire
6.60
SF (SFS)
PE
15.50
76
50
7/8“
Smooth copper tube
9.10
SF (SFS)
PE
22.50
76
50
1 ¼“
Smooth copper tube
12.70
SF (SFS)
PE
32.50
78
50
1 5/8“
Corrugated copper t
ube
17.30
SF (SFS)
PE
42.20
76
50
2 ¼“
Corrugated copper t
ube
20.80
SF (SFS)
PE
49.70
74.5
50
2. Materials for 50Ω RF cables
Your 50Ω radio frequency cable cable needs the best insulation materials to achieve
oustanding electrical performance for high-speed, error-free signal transmission.
Company E
Company R
LDPE
BP 8063
25 %
LDPE
Equistar NA-217-000
30 %
HDPE
Borealis HE1105
75 %
HDPE
Equistar M 5370 WC
70 %
Nucleation
Dow DGDA-6923 NT
0.2 %
Nucleation
Azodicarbonamid + Irga
nox
0.3 %
Foaming
Carbon dioxide CO2
Foaming
Carbon dioxide CO2
2. Materials for 50Ω RF cables
Other suitable materials for RF cable production are:
• HDPE: Borealis HE 1104
• MDPE: BP MD 8007
• HDPE: Dow HDGDA-6944
• LDPE: Dow DFDA-1253
• Nucleation: Borealis 1102
Actually SIEBE and DOW has closed a secrecy agrreement for the
developing of new materials for high frequency cables. The first step of
the cooperation is the developing of a new nucleation system, which will
be introduced in 2003.
2. Materials for 50Ω RF cables
• Comparison of Borealis Polyethylene
The value is too
high for RF Cable.
HE1102
ME1104
HE1105
Type
HDPE
MDPE
HDPE
Density(kg/m3)
948
932
947
MFR(g/10min)
5.0
3.0
3.3
OIT(min)
40
30
30
Dielectric
Constant(1Mhz)
2.4
2.30
2.33
Nucleating Agent
included
5~10% HE1102
5% Polyone 207-FT-50
(5% zodicarbonamide)
Max. Expansion
75%
80%
81%
Main Application
CATV
CATV, RF
RF
2. Materials for 50Ω RF cables
• Comparison of HD Polyethylene
Important
M5370WC
DGDA-6944
HE1105
Type
HDPE
HDPE
HDPE
Density(kg/m3)
953
965
947
MFR(g/10min)
7.0
8.0
3.3
OIT(min)
NA
50
30
Dielectric
Constant(1Mhz)
2.34
2.34
2.33
Nucleating Agent
NA
0.1~0.3% DFNA0012NT/0078NT
5% Polyone 207-FT-50
(5% zodicarbonamide)
Comments
Narrow Molecular
Weight distribution
Together with
DFDA-1233NT
RF
2. Materials for 50Ω RF cables
• Comparison of LD Polyethylene
NA217-000
BP8063
DFDA-1253NT
Type
LDPE
LDPE
LDPE
Density(kg/m3)
923
923
919
MFR(g/10min)
5.6
1.5
1.8
Dielectric
Constant(1Mhz)
2.28
NA
2.27
Comments
Medium Molecular
Wieght
2. Materials for 50Ω RF cables
For the inner skin, we recommend the “low loss“
LPDE:
• BOREALIS LE 6006
•Low Density Compound
• Density 918kg/m3
• MFR 0.3g/10min
• Dielectric Constant(1MHz) 2.29
3. Physically Foaming Agents
SIEBE offers today gas injection systems SGI for following gases:
1. Carbon dioxide CO2
2. Nitrogen N2
3. Argon Ar
4. Helium He
On SIEBE extrusion lines for high frequency cable production today
mainly CO2 is used as foaming agent.
3. Physically Foaming Agents
T r e ib m itte l
F orm el
M o lm a s s e
S ie d e p u n k t
D if f u s io n
L ö s lic h k e it
[g /m o l]
[°C ]
[x * N 2]
[x * N 2]
[1 0 1 3 m b a r ]
n -B u ta n
C H 3(C H 2)3C H 3
5 8 .1
-0 .5
ca.
?
0 .1
i-P e n ta n
(C H 3)2C H C H 2C H 3
7 2 .2
2 8 .0
?
ca. 1000
K o h le n d io x id
CO2
4 4 .0
-7 8 .4
ca. 1
ca. 10
S tic k s to f f
N2
2 8 .0
-1 9 5 .8
( := ) 1
( := ) 1
R 11
C F C l3
1 3 7 .4
2 3 .8
?
?
C H C l3 C F 3
1 5 2 .9
2 7 .8
ca.
?
(T r ic h lo r f lu o r m e th a n )
R 123
100
W asser
H 2O
H e liu m
He
1 8 .0
1 0 0 .0
5
-
4 .0
-2 6 9 .0
60
0 .2 5
3. Physically Foaming Agents
Advantages of CO2:
Higher solubility coefficient than nitrogen N2
→ Higher max. foam degree
→ Better cell structure
→ Better attenuation
→ More stable process
→ Slower expansion
→ Higher production speeds
3. Physically Foaming Agents
Price comparison CO2 to N2:
Carbon dioxide CO2: € 67.00 for 25 kg
Nitrogen N2:
€ 20.00 for 25 kg
The CO2 consumption for the production of 1 5/8“ with a
production speed of 8 m/min is approx. 2 kg/h.
4. Extrusion Line for 50Ω RF cable
Innovation is the key to any successfull enterprise. At SIEBE, we
are committed to the development of high-speed 50Ω RF cable
extrusion lines and processing procedures that bring innovative
solutions with highest productivity and excellent quality to your
business. Our team of scientists and technicians is dedicated to
technical precision, quality and reliability in every product we
make.
4. Extrusion Line 5/8” – 2 1/4”
The SIEBE high-speed 50 OHM RF cable extrusion 5/8“ – 2 ¼“ is basically consisting of:
2 Pay-offs for reels up to 2.500 mm flange diameter
1 Sizing / calibration unit
1 Dual disc capstan 1000 – 1200 mm
1 Pushing caterpillar 1500 – 2000 mm
1 Ultrasonic conductor cleaning station (mainly used for smooth copper tube)
1 HF conductor preheating
1 Skin extruder HSP 45-25D with crosshead and vacuum pump for tubing
1 Diameter gauge for skin diameter
1 Cooling trough with dryer for skin layer (2m length)
1 Gas injection foam extruder 125-33D GI with special extrusion gear pump and crosshead
1 Gas injection system SGI-C
1 Special RF cable calibration unit
1 Special RF telescope cooling trough (length 10 m) with one capacitance measuring tube
1 Wandexe
1 Dip cooling trough (min. 70 m for high production speed) with capacitance and special cable dryer
1 Diameter gauge
1 Pushing caterpillar (1.500 – 2000 mm)
2 Take-up up to 2.500 mm flange diameter Take-up
1 State-of-the-art electrical control and visualization system
4. Extrusion Line 5/8” – 2 1/4”
Cable
Conductor
Conductor
Insulation
Insulation ∅
Production speed
5/8“
Copper wire
6.60
SF (SFS) P
E
15.50
50 m/min
7/8“
Smooth copper tube
9.10
SF (SFS) P
E
22.50
30 m/min
1 ¼“
Smooth copper tube
12.70
SF (SFS) P
E
32.50
15 m/min
1 5/8“
Corrugated copper tub
e
17.30
SF (SFS) P
E
42.20
9 m/min
2 ¼“
Corrugated copper tub
e
20.80
SF (SFS) P
E
49.70
5 m/min
∅
4. Extrusion Line 5/8” – 2 1/4”
VSWR
The machine performance will mainly influence the return loss
(VSWR).
For our machine we guarantee best values for VSWR over the
whole frequency range.
Frequency range
VSWR
10 – 1000 MHz
≤ 1.10
1000 – 1700 MHz
≤ 1.10
1700 – 2500 MHz
≤ 1.10
2500 – cut off MHz
≤ 1.35
4. Extrusion Line 5/8” – 2 1/4”
VSWR
Depending on the frequency operation range of RF cables from 5.5 MHz up
to 3 GHz, error distances from 44 mm – 25 m will influence the cable quality.
Therefor all line components like caterpillars, double disk capstan, pulleys,
all motors and gears are not allowed to cause any periodically error in the
mentioned range
Variation line speed
≤ 0.1 % of setpoint
Variation tensile force
≤ 5 % of setpoint
Max. frequency peak
≤ - 60 dB%
4. Extrusion Line 5/8” – 2 1/4”
VSWR
RL(dB)
VSWR
Γ
RL(dB)
VSWR
Γ
RL(dB)
VSWR
Γ
RL(dB)
VSWR
Γ
46.0
1.01
0.00498
26.0
1.11
0.0521
17.7
1.30
0.130
8.0
2.32
0.398
40.0
1.02
0.00990
25.0
1.12
0.0566
17.0
1.33
0.141
7.0
2.61
0.445
37.0
1.03
0.0148
24.0
1.13
0.0610
16.0
1.38
0.158
6.02
3.01
0.500
34.0
1.04
0.0196
23.5
1.14
0.0654
15.0
1.43
0.178
5.0
3.56
0.562
32.0
1.05
0.0244
23.0
1.15
0.0698
14.0
1.50
0.200
4.0
4.42
0.631
30.4
1.06
0.0291
22.0
1.17
0.0783
13.0
1.58
0.224
3.01
5.85
0.707
29.0
1.07
0.0338
21.5
1.18
0.0826
12.0
1.67
0.250
2.0
8.72
0.794
28.0
1.08
0.0385
20.7
1.20
0.0909
11.0
1.78
0.282
1.0
17.39
0.891
27.0
1.09
0.0431
20.0
1.22
0.100
10.0
1.92
0.316
0.5
34.75
0.944
26.4
1.10
0.0476
19.0
1.25
0.112
9.0
2.10
0.355
0.0
Infinity
1.00
4. Extrusion Line 5/8” – 2 1/4”
VSWR
Return Loss
Voltage standing Wave Ratio
Reflection Coefficient
RL = -20*log|G| dB
VSWR =
G=
4. Extrusion Line 5/8” – 2 1/4”
Attenuation
Please note that the excellent line performance is only partly responsible for
the achieved cable attenuation. The attenuation is mainly influenced by the
used process materials for the dielectric. SIEBE is only responsible for the
foaming process. We guarantee a homogeneous fine foam with closed cells
and without holes, and a foam density ≤ 0.20 g/cm3, measured on samples of
the cable production.
4. Extrusion Line 5/8” – 2 1/4”
Production performance 1 5/8”
Dielectric
Physically foamed PE
Density dielectric
≤ 0.20 g/cm3
OD dielectric
42.2 ± 0.5 mm
Impedance
50 ± 1 Ω
Capacitance
76 ± 0.5 pF/m
Shorttime capacitance variations:
≤ ± 0.1 pF/m
Eccentricity
≤ 0.30 mm
Ovality
≤ 0.60 mm
Attenuation at 20 °C: 0,5 – 1000 MHz
0.045 – 2.49 dB/100m
Attenuation at 20 °C: 1000 – 1700 MHz
2.49 – 3.44 dB/100m
Attenuation at 20 °C: 1700 – 2750 MHz
3.44 – 4.67 dB/100m
VSWR: 10 – 2500 MHz:
≤ 1.10
4. Extrusion Line 5/8” – 2 1/4”
RFS
Pay-offs
4. Extrusion Line 5/8” – 2 1/4”
RFS
Sizing unit
4. Extrusion Line 5/8” – 2 1/4”
RFS
Ultrasonic cleaning
station
4. Extrusion Line 5/8” – 2 1/4”
Ultrasonic Wire Cleaning:
Wire cleaning can be improved by means a new highly intensive ultrasound process. In this process very
high ultrasonic power is concentrated in a small cleaning area, that surrounds the wire to be cleaned. This
induces a very intensive field of caviation. The sound intensity amounts to more than thousands times the
value reached by common ultrasonic baths. We offer that procedure in form of a fully automatic unit
comprising a cleaning, rinsing and drying section.
The compact machine will be provided with PLC interface, text display and automatic switching between the
tanks. The machine is designed for 24/7 operation.
Pre-Cleaning → Cleaning → Air-Wiping → Rinsing → Drying
In case of heavy dirt, additional alkaline cleaning agents can be used. We recommend SurfaClean V149
from Kiesow GmbH & Co. KG, Germany.
For further information for the ultrasonic cleaning station please see: www.hielscher.com
For further information for the alkaline cleaning agent please see: www.kiesow.org
4. Extrusion Line 5/8” – 2 1/4”
Sizing & Cleaning:
To achieve good product quality, a well sized and clean
conductor is required. If the conductor is not clean
enough, an sizing and cleaning unit should be installed
inline.
Clean copper surface:
→ Reduced diameter and capacitance variations
→ Improved adhesion
→ Improved electrical transmission
4. Extrusion Line 5/8” – 2 1/4”
RFS
Double wheel capstan
and pushing
caterpillar
4. Extrusion Line 5/8” – 2 1/4”
RFS
HF preheating station
and skinextruder
4. Extrusion Line 5/8” – 2 1/4”
EUPEN
Crosshead and
calibration unit
4. Extrusion Line 5/8” – 2 1/4”
EUPEN
Foam extruder and
gravimetric dosing
station
4. Extrusion Line 5/8” – 2 1/4”
RFS
Foam extruder
4. Extrusion Line 5/8” – 2 1/4”
Cooling trough
4. Extrusion Line 5/8” – 2 1/4”
EUPEN
Cable dryer, diameter
gauge and length
counter
4. Extrusion Line 5/8” – 2 1/4”
EUPEN
Pulling caterpillar and
take-ups
4. Extrusion Line 5/8” – 2 1/4”
4.Extrusion Line 5/8” – 2 1/4” - C/D - PC
4. Extrusion Line 5/8” – 2 1/4”
4. Extrusion Line 5/8” – 2 1/4”
SIEBE C/D plane:
C/D plane is a simultaneous graphical display of final capacitance and diameter by a violett cross and
its time history in green. The capacitance value is electronically delayed to coincide locally with the
diameter measurement. A box centered around the setpoints of C and D indicates the tolerance field,
inside which the trajectory of the process must stay to have good production, according to the setup
limits.
• Dark blue:
Lines of constant extruder throughput / meter weight PE
• Black
Lines of constant foaming / dielectricity
:
• Light blue:
Lines of constant gas flow
The position of the actual measurement in reference to the dark blue solid line (line of constant
amount of PE per length) indicates directly, whether the extruder output and expansion ratio are
correct for the defined product properties:
• Position of cross above line: → too much output / line speed to slow
• Position of cross below line: → too little output / line speed to fast
• Position of cross at line left of setpoint: → output o.k., not enough gas
• Position of cross at line right of setpoint: → output o.k., too much gas
The position along the dark blue line may be varied by changing gas amount, distance of cooling
trough, wire temperature or melt temperature. The black lines are coordinates of constant expansion,
along or parallel to which the process may be moved by varying the linespeed without changing
extruder rpm and gas flow. The rlight blue lines are the curves of constant gas flow. To move along
this coordinate, it is necessary to change extruder rpm, leaving gas flow and line speed unchanged.
4. Extrusion Line 5/8” – 2 1/4”
Basic requirements for C/D plane:
1.
Round insulation
2.
High centrictiy
3.
Density of used PE is stored in the computer
4.
Dielectricity of used PE is stored in computer
5.
Capacitance tubes and diameter gauges are calibrated correctly
4. Extrusion Line 5/8” – 2 1/4”
4. Extrusion Line 5/8” – 2 1/4”
4. Extrusion Line 5/8” – 2 1/4”
4. Extrusion Line 5/8” – 2 1/4”
SIEBE FFT analysis and SRL prediction:
The transmission characteristics of RF cable are most thoroughly described by the cable´s structural
return loss (SRL). Typically the SRL is measured as a function of cable operating frequencies at the
finished cable.
With respect to SRL drop-outs, periodic cable parameter fluctuations are most critical. In the extrusion
process, such variations might result from extruder fluctuations, imbalances of rotating parts, periodic
line / capstan fluctuations, cyclic fluctuations in the foaming process, or periodic conductor pre-heating
non-uniformities.
In combination with the SIKORA measuring equipment the system allows to predict the SRL
behaviour up to cable operating frequencies of 5 GHz.In connection with the SIKORA Capacitance
2060 the system allows the reliable detections of SRL peaks connected with periodic capacitance
fluctuations having a magnitude of less than 3 fF/m. FFT spectrum analyses and SRL predictions
based on diameter data can be conducted using SIKORA Laser 2100 diameter gauge or eccentricity
unit Wandexe 2080. The system allow the reliable detections of SRL peaks connected with periodic
diameter fluctuations in the nano-meter range.
The SIEBE FFT / SRL system is developed at RFS, Germany.
4. Extrusion Line 5/8” – 2 1/4”
4. Extrusion Line 5/8” – 2 1/4”
4. Extrusion Line 5/8” – 2 1/4”
4. Extrusion Line 5/8” – 2 1/4”
4. Extrusion Line 5/8” – 2 1/4”
4. Extrusion Line 5/8” – 2 1/4”