Phase-Array Antenna Simulation Lab

Laboratory Instructions

Adjust the parameters in the control panel to modify the antenna array configuration.
Observe how changes affect the radiation pattern in the polar plot.
Use the "Beam Steering" mode to see how phase shifting changes the main lobe direction.
Record your observations in the results table for different configurations.
Answer the questions at the end to demonstrate understanding of phase-array principles.

Radiation Pattern Visualization

Antenna Array Configuration

Main Beam Direction: 0°

Phase-Array Antenna Theory

Phase-array antennas consist of multiple radiating elements with phase shifters that electronically steer the radiation pattern without physically moving the antenna. The array factor (AF) for an N-element linear array with uniform spacing d and progressive phase shift β is given by:

AF(θ) = |sin(Nψ/2) / sin(ψ/2)|

where ψ = (2πd/λ)sin(θ) + β, λ is the wavelength, and θ is the angle from broadside.

The main beam direction can be controlled by adjusting the phase shift β between elements. The beam steering angle θ₀ is related to β by:

θ₀ = arcsin(βλ / (2πd))

Simulation Controls

Number of Elements: 8

Element Spacing (d/λ): 0.5 Typical spacing: 0.5λ to avoid grating lobes

Phase Shift (β, degrees): 0 Controls beam steering direction

Beam Width Control: 1.0 Adjusts the directivity of the pattern

Operation Mode:

Broadside: β=0°, End-fire: β=±180°, Steering: adjustable β

Simulation Controls:

Simulation Results

Parameter	Value	Effect on Pattern
Main Beam Direction	0°	Broadside
Beamwidth (3dB)	25°	Angular width of main lobe
Sidelobe Level	-13.5 dB	Relative to main lobe peak
Grating Lobes	None	Appear when d/λ > 0.5

Lab Questions

How does increasing the number of elements affect the radiation pattern?
What happens to the main beam direction when you change the phase shift?
At what spacing do grating lobes appear? Why?
Compare broadside and end-fire array configurations.