Broadside Array Calculator
Calculate broadside array gain and half-power beamwidth (HPBW) using zero progressive phase.
3
Inputs
Live
Math
3
Related
Enter parameters and click Calculate to view results
Formula & Theory
Broadside: β = 0°, HPBW ≈ 50.8° / (N × d/λ)This formula is used to calculate antenna parameters for broadside array calculator.
Overview
The Broadside Array Calculator computes array factor gain, estimated total gain (dBi), and Half-Power Beamwidth (HPBW) for broadside uniform linear antenna arrays. In a broadside configuration, all elements are excited in phase ($eta = 0^circ$), concentrating maximum radiated power perpendicular ($90^circ$) to the array axis.
Input Guide
Enter Elements (N), Element Spacing (d/λ), Element Gain exactly in the units shown by this broadside array. Check the operating band, unit prefix, and decimal position before calculating; these are the inputs used by the formula.
- Elements (N).
- Element Spacing (d/λ) — use λ.
- Element Gain — use dBi.
Output Guide
The results describe the calculated broadside array values for the inputs you entered. Check each value against the available space, selected components, feed system, and operating conditions before making a final design decision.
How This Calculator Works
The Broadside Array uses Broadside: β = 0°, HPBW ≈ 50.8° / (N × d/λ). Supply Elements (N), Element Spacing (d/λ) (λ), Element Gain (dBi) in the displayed units, then use the calculated values as the first engineering target for this antenna arrays design or analysis.
Design Notes
A broadside array produces a main beam directed normal to the array axis. Maximum radiation occurs at $ heta = 90^circ$ when the progressive phase shift $eta$ is set to $0^circ$. The main beam half-power beamwidth (HPBW) is inversely proportional to total array aperture length ($L = N cdot d$), calculated approximately as $\text{HPBW} \approx 50.8^circ / (N \cdot d/\lambda)$. To avoid grating lobes (secondary main beams), element spacing ($d/\lambda$) should be kept strictly below $1.0\lambda$, with $0.5\lambda$ being the standard design choice.
Build and Tuning Notes
Constructing a broadside array requires equal phase feeding across all antenna elements using symmetric power divider trees (such as corporate feed networks). Validate the radiation pattern, sidelobe levels, and total gain using full-wave EM simulation software or near-field antenna measurement ranges. Ensure mutual coupling between closely spaced elements is accounted for to prevent active impedance mismatch.
Frequently Asked Questions
What defines a Broadside Antenna Array?
A broadside array is a linear antenna array where all elements are fed in phase ($eta = 0^circ$). This causes electromagnetic waves to constructively interfere perpendicular ($90^circ$) to the line of elements.
How is the Half-Power Beamwidth (HPBW) calculated for a broadside array?
For an electrically large broadside array, HPBW is estimated using $\text{HPBW} \approx 50.8^circ / (N \times d/\lambda)$ degrees, where $N$ is the element count and $d/\lambda$ is element spacing in wavelengths.
What is the difference between a Broadside Array and an End-Fire Array?
A broadside array radiates maximum power perpendicular ($90^circ$) to the array axis using in-phase excitation ($eta = 0^circ$). An end-fire array radiates along the array axis ($0^circ$ or $180^circ$) using progressive phase shifts ($eta = pm k d$).
Why is 0.5λ element spacing recommended for broadside arrays?
Spacing elements at $0.5\lambda$ maximizes directive gain while completely suppressing secondary main beams (grating lobes) from entering the visible spatial radiation region.
Alex Warren
B.Sc. in Electrical & Electronic Engineering (EEE)
Alex specialises in antenna design and wave propagation. His expertise helps ensure these calculators present practical RF concepts, useful design estimates, and clear engineering guidance for students, HAM operators, and wireless professionals.