Antenna Array Element
Understanding Array Elements
The element is the building block of every antenna array. Its design determines the array's frequency range, polarization capability, scan range, and cross-polarization performance.
Element Selection
| Element | BW | Dual-Pol | Profile |
|---|---|---|---|
| Patch | 5-30% | Yes | Low (lambda/20) |
| Stacked patch | 30-50% | Yes | Medium |
| Vivaldi (tapered slot) | 100%+ (3:1) | Dual (egg-crate) | High |
| Dipole | 50-80% | Dual | Medium |
| Open-ended waveguide | 40% | Dual | High |
Frequently Asked Questions
What is an array element?
A single radiating component in an antenna array. Types: patch (low profile), dipole (wideband), Vivaldi (ultra-wideband), waveguide (high power). Spacing 0.5 lambda for no grating lobes. Element design determines array performance.
Why does element spacing matter?
Spacing > 0.5 lambda at the highest frequency creates grating lobes (undesired radiation peaks). Spacing < 0.5 lambda causes strong mutual coupling and high scan impedance variation. 0.5 lambda is the standard compromise.
What is mutual coupling?
Energy radiated by one element couples to adjacent elements, changing their impedance and pattern. Strong mutual coupling (< -15 dB) causes scan blindness (array impedance mismatch at certain scan angles). Must be managed through element design.