Formula Used
Wavelength: λ = c / f
Total elements: N = rows × columns
Scan loss: Lscan = -10 log10(cos θ)
Array gain: Garray = Gelement + 10 log10(N × ηtaper × ηaperture) - Lscan - Ltotal
Aperture gain: Gaperture = 10 log10((4πA / λ²) × ηtaper × ηaperture × cos θ) - Ltotal
Final gain: selected method uses array, aperture, or the lower conservative value.
Beamwidth estimate: HPBW ≈ 50.8 / (elements across axis × spacing in λ × cos θ)
EIRP: EIRP dBW = 10 log10(transmit power watts) + final gain dBi
How To Use This Calculator
Enter the operating frequency first. Add the number of rows and columns. Enter the gain of one antenna element. Add element spacing in wavelengths or meters. Set the scan angle from broadside. Add taper efficiency, aperture efficiency, losses, phase bits, and transmit power. Press the calculate button. Review gain, beamwidth, EIRP, and grating lobe risk. Use CSV or PDF export for reporting.
Example Data Table
| Case |
Frequency |
Elements |
Spacing |
Scan Angle |
Element Gain |
Estimated Use |
| Compact panel |
3.5 GHz |
4 × 8 |
0.5 λ |
20° |
5 dBi |
Small communication array |
| Radar face |
10 GHz |
16 × 16 |
0.5 λ |
35° |
6 dBi |
High directivity planning |
| Wide scan test |
28 GHz |
8 × 8 |
0.6 λ |
50° |
7 dBi |
Grating lobe review |
Why Phased Array Gain Matters
A phased array uses many small radiators as one antenna. Each element adds field strength at the selected direction. Phase shifts steer the main beam without moving hardware. This makes the system useful for radar, satellite links, 5G panels, tracking systems, and test ranges. Gain is not only a number. It shows how well energy is focused.
Key Design Ideas
The calculator combines element gain, element count, taper efficiency, aperture efficiency, frequency, spacing, and scan angle. A larger array can produce higher gain. However, the increase is limited by losses and layout choices. Tight spacing can reduce grating lobes. Wider spacing can improve aperture size, but it may create unwanted beams during scan.
Scan Loss And Beamwidth
When the beam moves away from broadside, projected aperture becomes smaller. The calculator applies a cosine scan loss model. This is a practical first estimate for planar arrays. Real arrays can also lose gain from mutual coupling, feed loss, quantized phase shifters, radome loss, and element patterns. Use the output as a planning value, not a final chamber result.
Useful Output Checks
Array gain is estimated from coherent element addition. Aperture gain is estimated from physical aperture area and wavelength. The final gain uses the smaller practical value when selected. This avoids an overconfident result for sparse or inefficient layouts. Beamwidth estimates help compare horizontal and vertical steering precision. The grating lobe warning checks spacing, wavelength, and scan angle.
Engineering Notes
Use realistic efficiency values. A uniform feed has high gain, but higher sidelobes. A tapered feed can lower sidelobes, but it also reduces gain. Enter taper efficiency below one when amplitude weights are used. Enter losses in decibels for cables, splitters, phase shifters, connectors, and radome effects. For final work, validate the design with electromagnetic simulation and measured antenna data.
Practical Workflow
Start with the operating frequency and array size. Choose spacing in wavelengths if known. Then add element gain and total losses. Compare broadside and scanned cases. Save the CSV for spreadsheets. Use the PDF report for quick sharing. Recalculate after changing taper, efficiency, or angle. Small changes can alter gain, beamwidth, and grating lobe risk. Keep every assumption clear before comparing antenna alternatives in practice.
FAQs
What is phased array antenna gain?
It is the directional gain created when many antenna elements combine their fields. Correct phase alignment makes signals add in one direction. The calculator estimates that gain from element gain, element count, efficiency, scan angle, and losses.
Why does scan angle reduce gain?
A scanned beam sees a smaller projected aperture. The simple model uses cosine scan loss. At large angles, element patterns and mutual coupling can add more loss.
What spacing should I use?
Half wavelength spacing is a common starting point. It helps reduce grating lobe risk during scanning. Larger spacing can raise aperture size, but it may create unwanted beams.
What is taper efficiency?
Taper efficiency represents amplitude weighting loss. Strong taper can lower sidelobes, but it also reduces main beam gain. Use a value below one when the feed is not uniform.
Is aperture gain always the final gain?
No. Aperture gain is a physical area estimate. Array factor gain is based on coherent element addition. The conservative method uses the smaller value.
What does grating lobe risk mean?
It warns that spacing may allow extra main-like beams. This is more likely with wider spacing and wider scan angles. It is a planning alert, not a full pattern simulation.
Can I use this for radar panels?
Yes, for early radar panel estimates. Enter realistic element gain, spacing, losses, and scan angle. Final radar work should still use measured patterns and electromagnetic simulation.
Why include phase shifter bits?
Digital phase shifters create phase quantization error. More bits usually reduce this loss. The calculator estimates a small gain penalty from the selected phase resolution.