Compute patch size, length, and feed offset very quickly. Review dimensions for fabrication and tuning. Clean outputs support faster engineering decisions and documentation today.
| Frequency | εr | Height | Patch width | Patch length | Feed offset | Bandwidth |
|---|---|---|---|---|---|---|
| 2.45 GHz | 4.4 | 1.6 mm | 37.2343 mm | 28.8093 mm | 10.5482 mm | 1.1189% |
| 1.575 GHz | 2.2 | 1.6 mm | 75.2402 mm | 63.4351 mm | 23.2261 mm | 0.9319% |
| 5.8 GHz | 3.48 | 0.8 mm | 17.2679 mm | 13.6069 mm | 4.9820 mm | 1.5164% |
Patch width: W = c / (2f) × √(2 / (εr + 1))
Effective dielectric constant: εeff = (εr + 1)/2 + (εr - 1)/2 × (1 + 12h/W)^(-1/2)
Fringing extension: ΔL = 0.412h × ((εeff + 0.3)(W/h + 0.264)) / ((εeff - 0.258)(W/h + 0.8))
Effective length: Leff = c / (2f√εeff)
Patch length: L = Leff - 2ΔL
Ground plane estimate: Lg = L + k·h and Wg = W + k·h
Feed location estimate: xf = (L/π) × cos-1(√(Z0 / Redge))
Bandwidth estimate: BW% ≈ 100 × 3.77 × ((εr - 1)/εr²) × (h/λ0) × (W/L)
These equations provide a strong first-pass design. Final values should be validated with EM simulation and measured tuning.
A coaxial patch antenna calculator helps engineers size a rectangular microstrip radiator with speed and consistency. It converts operating frequency, dielectric constant, substrate thickness, and feed impedance into practical geometry. That reduces manual iteration during early design work. The tool is useful for wireless prototypes, embedded radios, telemetry devices, and laboratory experiments. It also supports faster comparisons between substrate options. When dimensions change, resonant behavior changes too. Quick estimates save effort before detailed simulation.
Patch width influences radiation and bandwidth. Patch length mainly controls resonance. Effective dielectric constant models the mixed electric field inside the substrate and air. Length extension estimates fringing at both radiating edges. Ground plane dimensions affect stability and pattern quality. The coax feed location matters because impedance changes across the patch length. A good feed point improves matching to common lines. Better matching reduces reflected power and helps preserve useful radiation.
This calculator gives a practical starting point for engineering decisions. Designers can compare low loss laminates, common FR4 boards, and thicker substrates without repeating long hand calculations. It also highlights when a design becomes physically large or bandwidth becomes narrow. Those insights are important in antenna packaging. Many compact products need a balance between board area, efficiency, and manufacturability. Early estimates help teams choose a feasible stackup before modeling the antenna in a solver.
The computed feed offset is an approximation based on assumed edge resistance. Real antennas shift because of finite grounds, connector effects, fabrication tolerance, and nearby enclosures. Use the results as a baseline, not a final certification value. After calculation, validate the patch in an EM simulator and tune the feed position during measurement. This workflow is common in RF development. It keeps concept selection fast while preserving engineering accuracy during later design stages.
Students, RF engineers, and PCB designers can use this calculator during concept studies and coursework. It is especially helpful when building single band prototypes for WiFi, ISM, telemetry, or custom sensor links. The outputs are readable, exportable, and suitable for design notes, reviews, and quick documentation.
It estimates rectangular patch width, effective length, physical length, guided wavelength, feed offset, and ground plane size for a coax-fed microstrip patch.
No. The feed point is an engineering estimate. Real feed placement shifts with connector geometry, finite ground size, soldering, and nearby housing materials.
Edge resistance varies with geometry and modeling assumptions. Allowing it as an input gives you a flexible way to match measured or simulated patch behavior.
Yes, but FR4 losses can reduce efficiency and shift resonance. It is fine for low cost prototypes, but low loss substrates usually perform better.
The bandwidth output is a first-pass approximation. Use it for comparison and planning, then confirm the final bandwidth through full-wave simulation and measurement.
Thickness affects fringing fields, effective dielectric constant, bandwidth, and feed behavior. Even small thickness changes can alter resonance and matching.
No. It speeds the initial design stage. EM simulation is still needed for final geometry, impedance tuning, radiation pattern checks, and production accuracy.
Model the antenna in an RF solver, build a prototype, measure return loss and resonance, then trim the feed position or patch length as needed.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.