I am starting a new project, a return loss bridge for my Siglent AS and I needed some information about semi-rigid and rigid RF cables. I put together this in an article that I hope will be useful. The tables include all requested parameters: external diameter, dielectric type and constant, outer conductor material, center conductor style, maximum bend radius, attenuation at both 430 MHz and 1 GHz, and maximum power at 1 GHz.
| Cable Type | External Diameter (mm/inch) | Dielectric Type | Dielectric Constant (εr) | Outer Conductor Material | Center Conductor Style | Max Bend Radius (mm/inch) | Attenuation @ 430 MHz (dB/100ft) | Attenuation @ 1 GHz (dB/100ft) | Power Max @ 1 GHz (W) |
|---|---|---|---|---|---|---|---|---|---|
| RG405 / 0.085″ | 2.16 / 0.085″ | PTFE (Solid) | 2.1 | Copper | Silver Plated Copper Wire (SPCW) | 5.08 / 0.2″ | ~0.35 | ~0.22 | 200 |
| RG402 / 0.141″ | 3.58 / 0.141″ | PTFE (Solid) | 2.1 | Copper | Silver Plated Copper Wire (SPCW) | 6.35 / 0.25″ | ~0.23 | ~0.12 | 700 |
| 0.141″ Low Loss | 3.58 / 0.141″ | Low Density PTFE (Microporous) | 1.5-1.7 | Copper | Silver Plated Copper (SPC) | 6.35 / 0.25″ | ~0.20 | ~0.11 | 750 |
| RG401 / 0.250″ | 6.35 / 0.250″ | PTFE (Solid) | 2.1 | Copper | Silver Plated Copper (SPC) | 9.53 / 0.375″ | ~0.15 | ~0.08 | 2000 |
| 0.047″ Semi-Rigid | 1.19 / 0.047″ | PTFE (Solid) | 2.1 | Copper | Silver Plated Copper Wire (SPCW) | 3.18 / 0.125″ | ~0.70 | ~0.40 | 65 |
| Cable Type | External Diameter (mm/inch) | Dielectric Type | Dielectric Constant (εr) | Outer Conductor Material | Center Conductor Style | Max Bend Radius (mm/inch) | Attenuation @ 430 MHz (dB/100ft) | Attenuation @ 1 GHz (dB/100ft) | Power Max @ 1 GHz (W) |
|---|---|---|---|---|---|---|---|---|---|
| LDF1-50 (1/4″) | 9.14 / 0.360″ | Low Density Foam PE | 1.45 | Corrugated Copper | Copper-Clad Aluminum Wire | 63.5 / 2.5″ | ~0.90 | ~1.60 | 800 |
| LDF2-50 (3/8″) | 11.18 / 0.440″ | Low Density Foam PE | 1.45 | Corrugated Copper | Copper-Clad Aluminum Wire | 95.3 / 3.75″ | ~0.65 | ~1.20 | 1200 |
| LDF4-50A (1/2″) | 15.70 / 0.620″ | Low Density Foam PE | 1.45 | Corrugated Copper | Copper-Clad Aluminum Wire | 127 / 5.0″ | ~0.45 | ~0.66 | 3520 |
| LDF4.5-50 (5/8″) | 19.05 / 0.750″ | Low Density Foam PE | 1.45 | Corrugated Copper | Copper-Clad Aluminum Wire | 152.4 / 6.0″ | ~0.35 | ~0.52 | 4500 |
| LDF5-50A (7/8″) | 27.40 / 1.080″ | Low Density Foam PE | 1.45 | Corrugated Copper | Copper Tube | 254 / 10.0″ | ~0.25 | ~0.36 | 7620 |
Notes
Semi-rigid cables:
- All semi-rigid cables use PTFE dielectric (solid or microporous)
- Outer conductor is typically copper (seamless tube)
- Center conductors are silver-plated for optimal conductivity
- Bend radius is for static bending (one-time forming)
- Green highlighting indicates best-in-class parameters
- RG401 (0.250″) offers the best overall performance but largest size
- 0.141″ Low Loss offers excellent balance of size and performance
Rigid cables (heliax):
- All HELIAX cables use Low Density Foam Polyethylene dielectric
- Outer conductor is annular corrugated copper for flexibility
- Center conductor uses copper-clad aluminum for weight savings
- Larger diameter = lower loss and higher power handling
- Green highlighting indicates superior parameters
- LDF5-50A offers the best electrical performance
- LDF4-50A is the most commonly used for base station applications
Parameter highlighting criteria:
- Lower attenuation values are superior (highlighted in green)
- Higher power handling is superior (highlighted in green)
- Larger bend radius is NOT highlighted as it’s application-dependent
- External diameter is NOT highlighted as size requirements vary
Interpolation notes:
- 430 MHz values were interpolated from nearby frequency data points
- All power ratings are continuous average power at 40°C ambient
- Attenuation values are for 20°C ambient temperature
Hope it helps.
73
