Product Overview and Engineering Role
The spring antenna is for modules, gateways, and handhelds on China’s license-free Sub-1 GHz band. Where the shell is short, the spring radiator takes the place of an external whip, so assembly stays simple and the near-field pattern stays controllable. Tune it together with the PCB ground plane, the matching network, and the metal window in the shell, to cut mismatch loss and stay inside the radiated-spurious limit. It fits water meters, valve-pit terminals, and small indoor gateways.
State the center frequency, bandwidth, and peak ERP limit in the Hardware Specification, and finish a link budget against the LoRaWAN Class A/C duty cycle. A volume job can include a soldering-fixture note and a VSWR sample-check standard.
Reliability and Site Conditions
Spring height is tightly tied to the nearby ground plane and to the metal window in the shell. A new shell or a new mold can move VSWR and the pattern. In production, fix the soldering fixture and the bend process so a hand pull does not fatigue the joint.
On site, stay inside the local license-free power and duty-cycle rules. Re-test VSWR and radiated spurious on the finished unit, and write down how high the spring sits and where nearby metal is, so a later fault is easier to trace.
Key Hardware Parameters
The table is the usual RF and mechanical build, for selection and for a bid’s technical schedule. Another Sub-1 GHz frequency, interface, or package height comes from the Hardware Specification and the Installation and Commissioning Guide. Order codes in the family can differ. The nameplate and the papers in the carton decide.
| Parameter | Specification | Notes |
|---|---|---|
| Frequency band | 470 MHz ISM (typical for China) | Other regional frequencies on request |
| Gain | 2～4 dBi | Depends on the ground plane and the enclosure |
| VSWR | <1.8 | Typical frequency |
| Polarization | Vertical linear polarization | Sensitive to the spring axis |
| Impedance | 50 Ω | On-board pad / IPEX |
| Power | Within radio and LoRa regulatory limits | Matches the gateway or module rating |
| Protection | Depends on the whole device enclosure | The spring itself is not a standalone IP part |
| Lead | Short jumper or a direct feed | Keep the mismatched length short |
| Operating temperature | -40～85 ℃ | As stated in the specification |
| Installation | PCB solder or a bracket | Clearance from the reference design |
Typical Deployments
Four placements come up when the radio scheme is drawn and the payback is estimated:
Water and valve pits
A small terminal in the pit, with the spring on the top or the side.
Meter concentrators and transformer areas
A gateway inside the distribution cabinet, so there is no external antenna to steal.
Agriculture and environmental stations
A low-power solar node, with a simpler structure against wind shake.
Warehouse and cold-chain read points
Fills the holes between racks, and layers coverage with a ceiling gateway.
Installation, Grounding, and Maintenance
- Keep the ground-plane clearance and the matching-network footprint from the reference design, so the spring does not couple closely to the metal shell and mismatch.
- Solder on a suitable temperature profile, so heat does not change the spring temper or the plating.
- After the unit is assembled, re-measure VSWR near 470 MHz and conducted and radiated spurious, as the certification requires.
- On an external IPEX jumper, control bend radius and length, and latch the connector so a pull does not work it loose.
- Stay inside the local ISM rules for transmit power, duty cycle, and antenna gain.
Ordering, Documentation, and Support
A hardware specification, dimension drawings, a wiring table, and sample projects come with the inquiry. Volume orders can include a sample review and inspection at the plant. Warranty and calibration follow the contract and the papers in the carton.