380-520MHz Low Profile Ceiling Antenna

This low-profile UHF ceiling antenna covers 380-520MHz with an omnidirectional 360 degree pattern and stands only 18mm off the ceiling, which makes it one of the least visible options for in-building distributed antenna systems. It is designed for the 380-400MHz, 400-450MHz and 450-520MHz sub-bands used by public safety and private mobile radio, and it accepts up to 50W through a single 4.3-10 or N-Type Female port.

Where a low-profile ceiling unit fits

In a DAS installation the antenna is the part everyone can see, and in hospitals, office floors, airports and command centres that visibility is often the objection that delays approval. An 18mm-deep white ABS housing sits tight against a suspended ceiling and reads as a light fitting rather than as radio equipment. At 280 x 280mm it also fits the standard ceiling tile grid, so installation does not require cutting a bespoke opening.

The low profile does not come at the cost of coverage shape. The radiator is designed for a 360 degree horizontal pattern so that each unit serves a roughly circular cell on a floor plate, which is what keeps the number of antennas per floor predictable during design.

Three sub-bands and what they mean

Gain is specified per sub-band rather than as a single figure, because a compact wideband radiator cannot deliver the same efficiency across a 140MHz span. From 380-400MHz the antenna provides 2dBi, from 400-450MHz it provides 2.5 ±0.5dBi, and from 450-520MHz it provides 3.5 ±0.5dBi. The progression follows the physics: the same physical aperture is a larger fraction of a wavelength at the top of the band, so efficiency improves as frequency rises.

For design work, use the sub-band figure that matches the channels actually deployed rather than the best-case number. A floor served mainly by 450-470MHz private radio will see roughly 3.5dBi, while a 380-400MHz public safety layer should be budgeted at 2dBi, which changes the antenna count per floor by a noticeable margin.

Specifications

DAS layout notes

Space ceiling units at roughly 10-20m depending on ceiling height, partition density and the sub-band in use; low-band coverage travels through walls more readily, so a 380-400MHz layer usually needs fewer antennas per floor than a 450-520MHz layer. Keep the antenna at least half a metre away from metal light fittings, sprinkler pipework and cable trays, all of which distort the omnidirectional pattern more than their size suggests. Do not mount the unit inside a metal enclosure or behind a metal ceiling panel, because the 360 degree pattern depends on the surrounding surface being reasonably transparent to RF.

Feed each unit with low-loss coaxial cable and keep connector torque within specification; at 50W the connector is the most common source of passive intermodulation in an indoor system. Where the same ceiling serves both public safety and commercial radio, verify the isolation between the two systems at the combiner rather than assuming the antenna provides it.

Customization and ordering

The connector can be specified as 4.3-10 Female or N-Type Female at order time, and the housing colour can be changed for installations where white is not the right match. Cable assemblies, mounting kits and OEM labelling are available, and a sub-band version can be tuned where only part of the 380-520MHz span is used.

Send the band plan, ceiling type, power level and quantity to sales@rfelement.com. Samples are typically ready in 3-5 working days and mass production in 15-25 working days.