Surface wave multipath signals in near-field microwave imaging

Area of Science:

• Electromagnetics
• Microwave Engineering
• Signal Processing

Background:

• Near-field microwave imaging systems are susceptible to signal corruption from multipath interference.
• Surface waves can propagate along antenna feed lines, exacerbating signal degradation in imaging systems.

Purpose of the Study:

• To analyze the impact of surface wave effects on multipath signals in near-field microwave imaging.
• To investigate methods for mitigating surface wave-induced signal corruption.

Main Methods:

• Experiments were conducted using a near-field microwave imaging array at varying heights above a coupling fluid tank.
• Antenna arrays with different feed line lengths immersed in the fluid were evaluated.
• Theoretical predictions were used to validate experimental findings.

Main Results:

• Surface waves were observed to corrupt received signals, particularly over longer transmission distances within the array.
• Signal corruption due to surface waves was eliminated by using sufficiently long antenna feed lines.
• The effectiveness of feed line length in mitigating surface waves was independent of antenna tip height.

Conclusions:

• Surface wave propagation is a significant source of multipath interference in near-field microwave imaging.
• Optimizing antenna feed line length is a viable strategy to eliminate surface wave effects and enhance signal quality.
• This finding has implications for improving the accuracy and reliability of microwave imaging systems.