Visualize radiation patterns (omni and sector) on a polar plot and a floor-plan heat map. Place up to 4 antennas, set EIRP and pattern type, and see combined signal coverage on a 30m × 30m grid.
The Antenna Pattern & Placement Simulator visualizes radiation patterns and combined signal coverage for up to four antennas on a 30m × 30m floor plan, helping engineers optimize antenna type, position, and orientation before physical installation. It is used in DAS design, in-building coverage planning, and public safety radio system layout.
This simulator uses the 3GPP antenna model for sector antennas: gain(θ) = −min[12·(θ/θ_3dB)², 20] dB, where θ_3dB is the half-power beamwidth. Omnidirectional antennas return 0 dB gain in all horizontal directions. The heat map combines RSSI from all enabled antennas using maximum ratio selection (best signal wins at each point), consistent with how distributed antenna systems operate in practice.
Path loss in the heat map uses the log-distance model with n = 3.2 and a reference loss of 47 dB at 1 m — typical for indoor NLOS environments at 800 MHz. The coverage percentage is computed over a 20 × 20 cell grid, with each cell evaluated at its center point. Engineers should treat the result as a relative planning tool rather than a precise field prediction.
NFPA 1221 Section 9.6 and IFC 510.4.1 require that 95% of the building floor area achieves −95 dBm minimum RSSI for public safety radio. TIA-TSB-88 provides technical guidance on propagation models for land mobile radio (LMR) systems. The 3GPP TS 36.942 antenna model used here is derived from ITU-R M.2135 standardized indoor propagation assumptions. For formal DAS design submissions, AHJs typically require a professional engineer-stamped link budget and coverage map rather than a simulator output alone.
Sector antennas (60°, 90°, 120°) provide higher gain in the boresight direction but create coverage nulls at the sides and rear — the front-to-back ratio in this model is capped at 20 dB. For linear corridors, 90° sector antennas pointed along the corridor axis maximize coverage per antenna. In open-plan offices, omnidirectional antennas at uniform spacing typically achieve better coverage uniformity. The orientation (boresight) parameter rotates the sector pattern; 0° points toward the top of the diagram (north). When designing to meet the 95% NFPA threshold, ensure the −95 dBm boundary shown in the heat map covers all corners and stairwell access points.
Select an antenna from the tab row and enable it using the checkbox. Choose a pattern type and set EIRP (from the EIRP Calculator), orientation, and position using the sliders. The polar plot updates in real time to show the radiation pattern for the selected antenna. The heat map shows combined coverage from all enabled antennas at the selected RSSI threshold. Adjust the coverage threshold slider to evaluate compliance at different signal levels — set it to −95 dBm for NFPA 1221 public safety compliance checks. The coverage percentage displayed below the heat map indicates what fraction of the floor area meets the threshold.
The HPBW is the angular width between the two −3 dB points on the radiation pattern. For a 90° sector antenna in this model, gain drops by 3 dB at ±45° from the boresight axis, giving an HPBW of 90°. The pattern rolls off to −20 dB beyond 120° from boresight.
Front-to-back ratio (FBR) is the difference in gain between the main lobe (boresight) and the rear of the antenna (180°). High FBR reduces interference and co-channel coupling in adjacent zones. In this model, FBR is approximately 20 dB for all sector patterns, consistent with typical indoor panel antennas used in DAS systems.
At 800 MHz with 20 dBm EIRP in a concrete building (n = 3.5), a single omnidirectional antenna covers approximately 800–1,200 sq ft at −95 dBm. A 10,000 sq ft floor typically requires 8–12 antennas depending on building geometry. Use the Antenna Coverage Radius calculator for a precise per-antenna area estimate.
Voltage Standing Wave Ratio (VSWR) measures impedance mismatch between the cable and antenna. A VSWR of 2:1 corresponds to a −9.5 dB return loss and a reflected power of 11%. High VSWR wastes transmit power and can damage the BDA output stage. For DAS antennas, VSWR should be below 1.5:1 (−14 dB return loss) at the operating frequency.
Sector antennas are generally not ideal for circular or open atrium spaces because their coverage footprint is wedge-shaped. Omnidirectional antennas mounted at the center or multiple sector antennas aimed outward provide more uniform coverage in these geometries. For atria taller than two floors, a vertical distribution strategy with antennas at multiple elevations may be required.
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