📡 Phased Array Antenna Gain

Array gain · scan loss · beamwidth · grating-lobe limit

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Array Geometry

Element & Scan

Results

Total elements
–
Broadside gain
– dBi
Scan loss
– dB
Gain @ scan
– dBi
Beamwidth X @ scan
– deg
Beamwidth Y @ scan
– deg
Aperture size
– cm
Grating-lobe-free scan limit
– deg
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📖 How to use

  1. Set the frequency and the array size — number of elements in X and Y (set N_y = 1 for a linear array).设置频率和阵列规模——X、Y 方向的阵元数(Y 向填 1 即为线阵)。
  2. Enter the element spacing in wavelengths (0.5 λ is typical and avoids grating lobes).输入以波长为单位的阵元间距(常取 0.5 λ,可避免栅瓣)。
  3. Give the single-element gain (≈5–8 dBi for a patch) and any amplitude-taper / efficiency loss.填入单个阵元增益(贴片约 5–8 dBi)以及幅度加权/效率损耗。
  4. Set the scan angle off broadside — the gain drops by the scan loss and the beam broadens by 1/cos θ.设置距法向的扫描角——增益按扫描损耗下降,波束按 1/cos θ 展宽。
  5. Use Gain @ scan as the antenna gain in the link budget; watch the grating-lobe limit if spacing > 0.5 λ.把扫描角增益作为链路预算里的天线增益;间距 > 0.5 λ 时注意栅瓣极限。
  6. Arrived via a ↗ link from the Link Budget? Click the return bar at the top to carry Gain @ scan straight back into the field you came from (the bar never appears on a direct visit).如果是点链路预算里的 ↗ 链接跳转而来,点顶部的返回条即可把扫描角增益直接带回原字段(直接访问不会显示返回条)。

Phased array gain & scanning

A phased array forms a beam by combining many small radiating elements with controlled phase. Adding elements raises the gain by 10·log₁₀(N), and steering the beam off broadside is done electronically (no moving parts) by progressively phasing the elements.

Formulas used

Broadside gain: G₀ = G_element(dBi) + 10·log₁₀(N) − L_taper, N = N_x·N_y

Scan loss: ΔG = 10·log₁₀(cos θ_scan) (projected-aperture model; real arrays lose a little more from the element pattern)

Beamwidth: HPBW ≈ 0.886·λ / (N·d) at broadside, broadening as 1/cos θ when scanned

Grating lobes stay out of the visible region while sin θ_scan ≤ λ/d − 1; with 0.5 λ spacing you can scan to the horizon without grating lobes.

This is a first-order model (uniform amplitude, ideal elements). All computation runs locally in your browser.

相控阵增益与扫描

相控阵通过对许多小辐射阵元施加受控相位来形成波束。增加阵元数使增益提高 10·log₁₀(N), 而把波束偏离法向是通过逐元移相电扫描实现的(无机械运动)。

使用的公式

法向增益: G₀ = G_阵元(dBi) + 10·log₁₀(N) − L_加权,N = N_x·N_y

扫描损耗: ΔG = 10·log₁₀(cos θ_扫描)(投影口径模型;真实阵列因阵元方向图还会多损失一点)

波束宽度: 法向 HPBW ≈ 0.886·λ / (N·d),扫描时按 1/cos θ 展宽

当 sin θ_扫描 ≤ λ/d − 1 时栅瓣不进入可见区;采用 0.5 λ 间距可扫描到地平线而无栅瓣。

这是一阶模型(均匀幅度、理想阵元)。全部计算在你的浏览器本地完成。