TBI ENGINEERING / RF INTERFACE REVIEW
Define band, impedance and rotating duty. Review a coaxial joint or a hybrid assembly with independent RF, power and data paths.
Configuration review for antenna systems, gimbals and rotating test equipment. Frequency, channel count, power, bore and speed are agreed per design.
FIRST DECISION / CENTER PASSAGE
A coaxial rotary joint carries an RF transmission path across relative rotation. The term high frequency slip ring is also used in sourcing, but the actual geometry and impedance control matter more than the label. A separate on-axis RF component and a hollow-shaft electrical ring solve different packaging problems.
| Your constraint | Review direction | Confirm before approval |
|---|---|---|
| RF connection on the rotation axis; no shaft passage needed | Separate coaxial rotary joint | Band, impedance, ports, flange, torque and complete connector envelope |
| A shaft, optical path or service line must remain clear | Custom clear-center / hybrid layout review | Exact bore clearance plus OD, installed length and routing; the reference photo does not prove this architecture |
| RF plus motor power, encoder or industrial Ethernet | Separate RF and electrical/data transmission definitions | Per-path currents and protocol tests as well as RF match/loss/isolation |
Industry architecture reference: SPINNER RF rotary-joint overview ↗. This source describes transmission approaches; its ratings and product claims are not TBI specifications.
Use MHz or GHz explicitly and name the reference impedance. State which RF channels operate together, the allowed transmitter-to-receiver leakage, and whether the same RF path must pass a bias supply. RF wattage does not establish a DC current rating. Enter the actual lower band edge; do not use “DC” as shorthand when DC continuity is unnecessary. A non-contact RF path may block DC.
| Decision input | Send with your RFQ | Written review output |
|---|---|---|
| Frequency and impedance | Lower/upper band edges with units; 50 ohm, 75 ohm or another reference impedance | Band and impedance for each individual RF channel; no picture-based rating |
| RF channels and coupling | Independent channel count, coaxial/waveguide interfaces and any bias requirement | Exact architecture, port map and isolation between stated port pairs |
| CW and peak power | Average/CW and peak definitions, waveform, pulse duration/repetition and load mismatch | Frequency, temperature, pressure/altitude and duty conditions for the approved model |
| Loss and match | Insertion-loss maximum; return-loss minimum or VSWR maximum | Agreed port reference planes, cable/adapter inclusion and full-band limits |
| Rotation-dependent behavior | Loss/phase variation, channel-to-channel phase tracking if relevant, RPM and motion | Limits over the agreed angle range and band; stationary measurements alone are insufficient |
| Installed envelope | Maximum OD/length, connector orientation, lead exit and required clear center passage | Actual mounting/torque reaction and any hybrid power/data assembly drawing |
A worksheet records your requirements. It is not a released datasheet or a completed acceptance report; no file is uploaded by downloading it.
Insertion loss describes forward transmission between defined reference planes. Return loss and VSWR describe reflection at a specified port and reference impedance. Low reflected power does not rule out dissipative loss, so matching alone cannot establish a low-loss channel.
Define whether connector launches, adapters and rotor/stator leads belong inside the quoted limit. If results from different fixtures are compared, agree calibration and any de-embedding first. Use the same band and conditions when comparing values. For two-port match measurements, terminate the opposite port in the agreed reference impedance and document all multiport terminations.
For a passive port with a common real reference impedance: ρ = (VSWR − 1) / (VSWR + 1), return loss = −20 log₁₀(ρ), reflected power = 100ρ²%. These examples are not TBI measurements or recommended acceptance thresholds.
| VSWR | Return loss | Reflected incident power |
|---|---|---|
| 1.2:1 | 20.83 dB | 0.83% |
| 1.5:1 | 13.98 dB | 4.00% |
| 2.0:1 | 9.54 dB | 11.11% |
A higher positive return loss means less reflection. None of these percentages describes total insertion loss, thermal capacity or system efficiency. Reference equations: R&S dB Calculator, VSWR converter ↗.
Give the allowed maximum-to-minimum change with rotation over the requested band. For coherent multi-channel systems, distinguish each channel's phase variation from the tracking of their phase difference. Rotation variation is sometimes termed WOW; static inter-channel phase matching is a separate requirement.
Name the transmitting and receiving port pairs, band and termination of other ports. A single isolation figure without these conditions cannot define every multi-channel path.
State average power and the meaning of peak power, waveform, pulse width, repetition, mismatch, ambient conditions and pressure/altitude. A low-duty request does not independently establish peak capability.
Measurement terminology reference: SPINNER ATC technical annex ↗. Agree your own configuration limits; no source-vendor rating is transferred to the illustrated component.
A rotating antenna or camera may need an RF feed, actuator power and control/data channels in one package. Record each path separately. A connector that passes RF need not support motor current, and an electrical ring arrangement need not meet an RF impedance target.
For hybrid designs, submit the clear-center requirement and complete installed envelope together. The flange, rotor connection, mounting restraint, cable bend radii and connector access can dominate the space requirement.
Hybrid integration examples: Everaxis RF category ↗ and Amphenol RF rotary-interface category ↗. These are industry references, not evidence of TBI affiliation or qualification.
Bring the RF band, feed power, phase sensitivity, mass/torque budget and continuous or oscillating duty. An RF review is separate from equipment-level flight, defense or environmental qualification.
State the camera/receiver format and the entire cable path. A 75-ohm request does not prove an SDI link. Keep digital-interface acceptance on the complete rotating assembly.
Compare the requested band at agreed rotor angles with controlled cable conditions. Continuous-rotation testing needs an engineered measurement path; a fixed VNA cable must not be twisted indefinitely.
Separate small-signal network measurements from RF power-loading qualification. Agree instrument input limits, fixture protection, environmental conditions and methods for each test. RF fixtures, cables and special tests need their own quotation scope; ordinary electrical-harness allowances do not cover them.
These are RF inspection planning inputs, not evidence of tests performed by this site. Ask which records are available for the proposed configuration before placing an order.
The terms can overlap in procurement. Specify the actual RF transmission path, band, impedance and rotating conditions. A general-purpose electrical signal ring is not automatically a controlled-impedance RF path.
The reference does not demonstrate a clear shaft passage. Treat it as a separate coaxial component. If a clear bore is required in the complete assembly, enter its exact size and request a hybrid layout review.
No. Give the exact connector part/version and impedance for every channel, including cables and adapters. A visually similar connector or protective cap does not establish impedance or frequency performance.
No. VSWR/return loss describe reflection at a port. Insertion loss describes forward transmission between stated reference planes. Ask for both over the required frequency band and operating conditions.
Only when that exact RF design permits it. State DC bias separately. High-current actuator power generally needs separately reviewed electrical paths; never infer DC capability from RF wattage.
No. Identify the SDI format, devices, cable assembly and rotating test conditions. The RF path and the complete digital video link both need validation.
Request an available configuration-specific envelope/STEP drawing and agreed test records in the quotation. This page publishes no released TBI RF datasheet, measured S-parameters or qualification certificate.
No. It is a blank local download. Attach your completed worksheet and approved drawing in your own email client, or transfer the requirements into the web brief. Availability, price, delivery and acceptance terms need a written quotation.
Engineering method reviewed November 2, 2026. Model-specific results and available configurations require their own records.
BAND + IMPEDANCE + ENVELOPE
Start with frequency, impedance, channel count, power, motion and space. Request an available envelope/STEP drawing, configuration-specific RF limits and written quotation. Attach approved drawings and your completed worksheet in your own email client.
In the web configurator, define the required center passage, enter “No power circuits” if appropriate, select “RF coaxial — specify impedance” and add the band/power/acceptance details in your notes. Saved fields are preserved before a different-image choice. The worksheet is a separate download and is not automatically attached or uploaded.
Image reference Image 045 is an arrangement for discussion, not a released RF SKU. General dimensional requests can also start with the custom interface brief.
