Angle Maximum

The maximum steering angle is directly proportional to the wavelength, meaning a longer wavelength allows for a wider steering range,

while it is inversely proportional to the antenna spacing, meaning a larger distance between antennas results in a narrower steering range.

Caution: If the antenna spacing exceeds half the wavelength,  grating lobes will appear within the visible region, so you must always maintain d <= λ/2.

λ wavelength of RF center frequency d  distance between antennas

Example

The FOV is restricted primarily because individual antenna elements have low gain at wide angles, causing signal strength to drop sharply.

Steering the beam increases scan loss and broadens the beamwidth, which significantly degrades detection sensitivity and resolution.