Cable Assembly
Understanding Cable Assemblies
Cable assemblies are the lifeline of any RF system, connecting components, instruments, and subsystems. A poor-quality cable assembly can degrade system performance as much as a bad amplifier or filter. Every connection in the system contributes loss, VSWR, and potential failure.
Cable Assembly Types
- Test-grade (flexible): Precision connectors, phase-stable cable. Up to 70+ GHz. Used for VNA connections and lab measurements.
- System-grade: Semi-rigid or conformable cable with SMA/N connectors. System integration.
- Production (jumper): RG-series or LMR cable with standard connectors. Lower cost for production installations.
Key Specifications
- Insertion loss: Cable loss + connector loss. 0.5-3 dB/m depending on frequency and cable type.
- Return loss: > 20 dB at each connector and along the cable.
- Phase stability: Phase change with flexing, temperature, or vibration. Critical for phased arrays.
Frequently Asked Questions
What is a cable assembly?
A cable assembly is a complete RF interconnect: cable with connectors on each end, tested for electrical performance. Specified by cable type, connectors, length, frequency range, loss, and return loss.
What makes a good cable assembly?
Precision connector installation (proper strip dimensions, solder flow, center pin alignment), 100% electrical testing (return loss > 20 dB at every connector), appropriate cable for the application (phase-stable, low-loss, flexible), and proper labeling.
When should I use semi-rigid vs flexible cable?
Semi-rigid: best performance (lowest loss, best shielding, most phase-stable), but not flexible after bending. Used in fixed installations and inside equipment. Flexible: can be repeatedly bent and moved. Used for test connections and deployable systems.