PS635L-18G-F High Frequency Low Loss Phase Stable Coaxial Cable
Ultra-Low Insertion Loss & Exceptional Thermal Stability Rated Up to 18 GHz
Engineered for high-density precision microwave interconnects, the PS635L-18G-F combines expanded LD-PTFE dielectric insulation, a solid 1.57 mm silver-plated copper inner conductor, and a high-temperature Light Blue FEP jacket to achieve outstanding thermal endurance (-55°C to +200°C), superior flexibility, and low phase variation up to 18 GHz.
Max Frequency:DC-18 GHz
Velocity of Prop.：78%
Phase Stability ：±0.2 °/GHz
Outer Diameter:6.35mm
Structure & Construction Characteristics
| Layer | Element | Material | Construction (mm) | Nom. O.D. (mm) |
|---|---|---|---|---|
| Inner Conductor | Center Conductor | Silver Plated Copper | 1 / 1.57 | 1.57 |
| Dielectric | Insulation | LD-PTFE | – | 4.70 |
| Inner Shield | Flat Ribbon Shield | Silver Plated Copper Strip | – | 4.90 |
| Interlayer | Barrier Tape | High Temperature Aluminium Foil | – | 5.04 |
| Outer Shield | Braided Shield | Silver Plated Copper Wire | – | 5.55 |
| Jacket | Outer Sheath | Light Blue FEP | – | 6.35 |
Mechanical & Environmental Parameters
| Min. Static Bend Radius | 30.00 mm | Min. Dynamic Bend Radius | 60.00 mm |
|---|---|---|---|
| Weight | 0.092 kg/m | Operating Temperature | -55°C to +200°C |
Electrical & Mechanical Characteristics
| Impedance | 50 Ω | Capacitance | 88 pF/m |
|---|---|---|---|
| Velocity of Propagation | 78% | Max Operating Frequency | 18 GHz |
| Screening Effectiveness | > 90 dB | Dielectric Withstanding Voltage | 2500 V DC |
| Phase Change vs. Bending | ±0.2 °/GHz | Phase Change vs. Temperature (-45~+85℃) | ≤ 1500 PPM |
Attenuation & Power Handling @ 25℃ & Sea Level
Insertion Loss Calculation: IL = K1 * sqrt(F_MHz) + K2 * F_MHz [dB/100m]
Constants: K1 = 0.6923158, K2 = 0.000760
| Frequency (MHz) | Nominal Attenuation (dB/100m @ 25°C & Sea Level) | Max Power Handling (W @ 40°C & Sea Level) |
|---|---|---|
| 300 | 12.22 | 1,850 |
| 500 | 15.86 | 1,425 |
| 1000 | 22.66 | 998 |
| 2000 | 32.48 | 696 |
| 3000 | 40.19 | 562 |
| 6000 | 58.19 | 388 |
| 8000 | 68.00 | 332 |
| 10000 | 76.83 | 293 |
| 12400 | 86.53 | 261 |
| 16000 | 99.71 | 226 |
| 18000 | 106.56 | 211 |
Cross Reference & Direct Equivalent Replacement
The PS635L-18G-F low loss phase stable coaxial cable is engineered as a direct drop-in replacement for Times Microwave SFT142 / SFT-142, delivering matched 18 GHz high-frequency capability, identical mechanical dimensions (6.35 mm outer diameter), and equivalent phase stability under flexure.
Frequently Asked Questions
How does the fluorinated ethylene propylene (FEP) jacket improve environmental reliability in high-temperature RF applications?
The extruded FEP jacket offers an extremely wide operating temperature rating (-55°C to +200°C) with exceptional chemical inertness and UV resistance. Unlike standard PVC or polyurethane, FEP maintains mechanical stability without outgassing or softening during high-power Ku-band RF transmission or prolonged thermal cycling in aerospace cabins.
What makes the 2500 V DC dielectric withstanding voltage rating critical for high-altitude microwave systems?
The 2500 V DC rating reflects the high dielectric strength of the expanded LD-PTFE insulation structure. In unpressurized airborne electronics bays, this high breakdown voltage margin prevents corona discharge and voltage arcing across the 4.70 mm dielectric layer during peak RF pulse powers at high altitudes.
How does the 1500 PPM thermal phase change limit affect wideband phase tracking in radar receivers?
A maximum phase variance of ≤ 1500 PPM across the -45°C to +85°C temperature envelope guarantees that electrical path length changes remain within tight tolerances. This minimizes phase error drift between channels in multi-channel monopulse radar systems and phase-array receivers without requiring real-time software calibration.
