BOM CONSOLE · ANTENNAS AND RF COMPONENTS
A buyer opening an rf isolator sma line still has to name the band, the connector gender, and the power the internal load must survive. LinkScope Sourcing 34 writes that line into a factory request. The desk is an independent sourcing partner, not a ferrite workshop and not a stock room.
In a 2026 brief the useful starting row is often 50 ohm impedance, an SMA interface, a stated frequency range, and separate numbers for forward power rating and termination power. Isolation and insertion loss are buyer thresholds until a supplier attaches them to one model code. Polarization and radiation pattern stay blank when the line is a non-radiating isolator.
Open inquiry cards
Each row below is a question the quotation must answer. Example thresholds are buyer-authored check values from a worked 2026 desk note. They are not measurements published by this site, and they are not a promise that a factory will meet them.
| Ledger row | What to demand | Example check value |
|---|---|---|
| Frequency range | Start and stop, plus the point where the limit is specified | 2.0 GHz to 4.0 GHz |
| Impedance | System impedance at the connector reference plane | 50 ohm |
| Insertion loss | Maximum in-band S21, temperature stated | 0.6 dB at 25 C |
| Isolation | Minimum reverse attenuation the buyer will accept | 18 dB |
| VSWR and return loss | Both, because a 1.30:1 VSWR converts to about 17.7 dB return loss | 1.30:1 and 17.7 dB |
| Power rating | Forward average, peak, and the internal termination rating as three fields | 10 W forward, 20 W peak, 2 W load |
| Connector | Series, gender, and the drawing the supplier cites | SMA female, both ports |
| Evidence file | Datasheet revision date and an S-parameter plot tied to the model code | Revision dated in 2026 or the issue actually quoted |
Gain is the wrong column for a passive isolator. If the bill also carries an amplifier, put transmit power and gain on that amplifier row. Measurement accuracy and calibration traceability belong to the plot: ask whether the vector network analyzer calibration was SOLT at the SMA plane. Connector mating cycle, when the datasheet states one, tells you whether a refurbished body is plausible. Ingress protection matters for an outdoor radio, and it is usually irrelevant on a lab bench.
A passive isolator line often has no equipment authorization of its own. The radio it protects may. Buyers check 47 CFR Part 2 Subpart J on eCFR for the transmitter model, not for the ferrite part, and they still ask the supplier what mark, if any, applies. IEC connector sectional specifications describe geometry. A matching SMA outline does not prove isolation.
Background: a 2026 bench PA at 2.4 GHz can reflect energy when the antenna VSWR rises. Process: the buyer writes 10 W forward and a termination rating that can absorb the expected reflection, example 2 W. Result: factories quote the load, not a headline isolation figure alone. This is a worked route, not a completed customer project.
A low-level receive path cares more about insertion loss than about watts. Receiver sensitivity of the downstream radio is someone else’s number. The isolator row should state a maximum insertion loss, example 0.4 dB, and a frequency range that matches the filter, not the whole catalog family.
A rack unit patch panel may need a short SMA jumper plus the isolator. Mounting is then a bracket question. Environmental rating can stay “indoor, 10 C to 40 C” unless the rack is outdoors. Quantity is often pieces per rack, not a site license.
A cryogenic part does not inherit the room-temperature ledger. Read the cold-stage path before copying a 25 C insertion-loss cell into a 4 K request. Magnetic shielding becomes a line item there.
Three limits sit on every route. Isolation outside the stated frequency range is not the in-band number. The internal termination power rating is often lower than the forward power rating. A room-temperature S21 plot does not describe a cryogenic stage. The desk does not run the network analyzer.
Ask for the current datasheet, the revision date, and the S-parameter file. A family brochure that says “SMA isolators” is not a substitute. If two quotes cite different revisions in 2025 and 2026, keep them in separate columns.
ISO 9001, when a factory offers it, should name the certification body and the expiry. This desk has not audited that certificate. An NRTL file is often the wrong artifact for a passive coaxial part; ask the supplier what safety document, if any, they intend to send.
A new unit may carry a clearer connector mating-cycle history. A refurbished unit may cover a discontinued band when the quote states condition, the test date, and the warranty text. Neither side is ranked here. The buyer records which evidence arrived.
A vendor-marked part may sit on a radio maker’s approved list. A compatible part may still be workable when frequency range, power rating, and a current plot match the host. Compatibility is not established by a photograph of an SMA nut. See the circulator comparison if the port count is still open, or the procurement note for the longer checklist.
There is no file-upload service on this desk. Type the bill row into the requirement field: frequency range, 50 ohm or another impedance, power rating, SMA gender, quantity, US destination, and the delivery window you want the factory to confirm. Optional budget needs a currency and a per-piece or whole-order basis.
High-end, mid-range, budget, or undecided is your preference for which factories to approach. It is not a grade those factories have already earned. The contact page keeps handling notes beside the same field set. The BOM workflow shows how to compare two replies once they return.
QUALIFIED BUSINESS BUYERS
The desk can ask factories for quotations after the isolator line is written down.
Eligibility applies to qualified business buyers and is confirmed after we review your product, quantity, destination, and sourcing requirements.