RFID Portal Read Range for Electronics Receiving — Impinj R420 + Times-7 Far-Field

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Laboratory · Read Range Calculation

RFID dock door portal calculation for electronics retail. Impinj R420 + Times-7 Far-Field (9 dBi). EUR pallet on forklift. Metal shielding. 2 vs 4 antennas. Three chips: Higgs-3, M750, M730.

Reader
Impinj R420
ETSI EU · 33 dBm · 4-port
Antennas
Times-7 Far-Field ×4
9 dBi · RHCP · LMR-400 4m
ETSI limit
36.0 dBm EIRP
4 W ERP
Pallet
EUR 1200×800 mm
up to 60 boxes · 0.5 m/s
01 · Link Budget 

Input Parameters and ETSI Correction

ParameterValueNotes
Frequency 866 MHz ETSI EU Lower Band
Wavelength (λ) 0.346 m ~35 cm
TX Power R420 33.0 dBm Max ERP 2 W
Cable LMR-400, 4 m −1.2 dB @ 866 MHz
Times-7 antenna gain +9.0 dBi Far-Field RHCP
Calculated EIRP 40.8 dBm ⚠ Exceeds ETSI — reduction required
EIRP after ETSI 36.0 dBm 4 W ERP · TX reduced to ~29 dBm
Polarisation loss CP→Linear −3.0 dB Circular antenna → linear tag
Stretch-wrap loss −1.5 dB ε_r ~2.3 polyethylene
Fading margin −6.0 dB Portal dynamics, multipath
Alien Higgs-3 · TV, MDA
~2.8 m
Practical: ~1.8 m
Sensitivity: −18 dBm · Max PL: 43.5 dB
Large SKU
Impinj M730 · Accessories
~4.4 m
Practical: ~2.8 m
Sensitivity: −22 dBm · Max PL: 47.5 dB
Small SKU
Impinj M750 · Laptops
~5.6 m
Practical: ~3.5 m
Sensitivity: −24 dBm · Max PL: 49.5 dB
Mid SKU ✓ Recommended
⚡ Key finding: M750 vs Higgs-3 tag price difference is ~€0.03–0.05/piece. Read rate difference: 97–99% vs 85–90% for metal electronics. ROI is obvious at any volume.
ChipSensitivityTotal LossMax PLR_max (theor.)R_max (pract.)
Alien Higgs-3 −18 dBm 10.5 dB warn|43.5 dB ~2.8 m ~1.8 m
Impinj M730 −22 dBm 10.5 dB ok|47.5 dB ~4.4 m ~2.8 m
Impinj M750 −24 dBm 10.5 dB ok|49.5 dB ~5.6 m ~3.5 m
02 · R_max by chip 

Read Range — Three Chips

ConfigurationPallet coverageRead Rate electronicsResult
2 antennas (overhead beam) 70–80% 85–90% Non-metal goods only
4 antennas (sides + top) 95–98% 97–99% Recommended for electronics
03 · Antennas: 2 vs 4 

Antenna Configuration for Electronics

Pallet layerDepthExtra metal lossR_max M750R_max Higgs-3
Layer 1 (top) 0–30 cm 3 dB ~3.0 m ~1.5 m
Layer 2 30–60 cm 6 dB ~2.2 m ~1.1 m
Layer 3 60–90 cm 10 dB ~1.4 m ~0.7 m
Layer 4 (bottom) 90–120 cm 15 dB ~0.8 m ~0.4 m ⚠
04 · Pallet layers 

Pallet Layer Metal Shielding

ParameterAlien Higgs-3Impinj M750M750 advantage
Sensitivity −18 dBm −24 dBm +6 dB
R_max (pract., ramp) ~1.8 m ~3.5 m 2.0× range
Readable pallet layers 1–2 layers 3–4 layers +2 layers
Read Rate electronics 85–90% 97–99% +10%
Tag cost €0.08–0.12 €0.10–0.15 +25% / ~€0.04
05 · Higgs-3 vs M750 

Chip Comparison for Dock

✓ Tag placement: side face of box
  • ✓Visible from 2 portal sides — left and right antennas
  • ✓Less shielding from metal contents inside
  • ✓Stretch-wrap does not fully block the side face
  • ✓Readable regardless of pallet rotation on forklift
✗ Avoid placement
  • ✗Top face — visible to only 1 antenna, blocked by layer above
  • ✗Front face — one side only, may face wall
  • ✗Rear face — pressed against adjacent box on pallet
06 · Tag placement 

Correct Tag Placement on Box

#FactorImpactWhere critical
1 Multipath from metal enclosures ±10–20 dB Pallets with electronics
2 Tag shadowing between boxes 5–15 dB Lower layers of dense pallet
3 Stretch-wrap (multi-layer) 1–3 dB Tightly wrapped pallets
4 Higgs-3 chip variation ±2–3 dB Different tag batches
5 EM noise (warehouse WiFi, other RFID) 3–8 dB Active warehouse zone
6 Box orientation on pallet 0–3 dB RHCP partially compensates
7 Near-field (d < 0.2 m) unpredictable Not applicable for portal
07 · Model limitations

What Friis Does Not Account For

Why does electronics retail require 4 antennas instead of 2?
Metal enclosures of laptops and tablets cause shielding up to 15 dB for lower pallet layers. With 2 overhead antennas, lower layers remain in dead zones — read rate 85–90%. 4 side-mounted antennas cover all pallet angles and achieve 97–99%.
Why does R420 have enough time to read all tags on a pallet?
A forklift crosses the read zone (~2 m) in ~4 seconds at 0.5 m/s. R420 reads up to 1100 tags/sec — 60 tags need only 0.05–0.1 sec. The bottleneck is antenna coverage and metal shielding, not reader speed.
Why is M750 better than Higgs-3 for electronics on the dock?
M750 is 6 dB more sensitive (−24 vs −18 dBm) — that is double the range by Friis. On the ramp this means reading 3–4 pallet layers instead of 1–2. Read rate with M750: 97–99%, with Higgs-3: 85–90% for metal-containing electronics.
rfid.org.ua · RFID Laboratory · Dock DoorModel: Friis · ETSI EN 302 208 · 2026-02-27

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