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Patch Antenna Calculator
Calculators / Patch Antenna
Microstrip Patch Antenna
Calculator
Calculate the patch width, patch length, effective dielectric constant, and resonant frequency of a rectangular microstrip patch antenna using the Bahl & Trivedi transmission-line model.
Radiating Patch
Dielectric Substrate
Ground Plane
⚙ Patch Antenna Engine
Design frequency for the patch resonance
Common: 0.8, 1.6, 3.2 mm (FR4)
FR4 ≈ 4.4, Rogers RO4003C ≈ 3.55, PTFE ≈ 2.1
FR4 ≈ 0.02, RO4003C ≈ 0.0027, PTFE ≈ 0.0002
Advanced Parameters
mm
Typical copper: 35 µm (1 oz), 70 µm (2 oz)
Edge feed: simple, Zin ≈ 200–300 Ω at edge
mm
0 = edge. Inset reduces input impedance to 50 Ω
Sets inset-feed depth for impedance match
Calculated Results
Patch Width (W)
—mm
Patch Length (L)—
Eff. Length (Leff)—
Wavelength (λ)—
λ/2 in substrate—
Eff. Permittivity (εreff)—
Length Extension (ΔL)—
Radiation Resistance (Rr)—
Quality Factor (Q)—
Bandwidth (BW)—
Gain (approx.)—
Input Impedance (Zin)—
Enter values above to calculate.
📖 Design Theory
A rectangular microstrip patch is a conducting patch on a grounded dielectric substrate. It resonates when its length L ≈ λg/2 in the substrate medium.
Step 1 — Patch Width
W = c / (2fr √((εr+1)/2))
Step 2 — Effective εr
εreff = (εr+1)/2 + (εr-1)/2 · (1+12h/W)^-½
Step 3 — Patch Length
L = c/(2fr√εreff) − 2ΔL
ΔL = fringe extension (Hammerstad formula)
The substrate thickness h and εr set the wavelength compression. Thicker/lower-εr substrates give wider bandwidth but larger patch size.
📡 Substrate & Field Visualiser
Live Simulation
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◉ Cross-Section & Radiation Pattern
Display Mode
εr Tuning
4.4
1.012.0
h/λ ratio
0.02
Cross-Section
Top View (Patch)
ℹ
Design Insights
Enter frequency and substrate parameters to see live design insights and trade-offs.
Common Applications
WiFi & Bluetooth
2.4 / 5 GHz patch antennas on PCBs for IoT devices, routers and wearables.
GPS / GNSS
1.575 GHz (L1) circularly polarised patches widely used in navigation systems.
Radar & 5G mmWave
Patch arrays at 24–77 GHz in automotive radar and 5G base-station tiles.
Aerospace & Defence
Low-profile conformal patch arrays on aircraft fuselages and missiles.
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