A Miniaturized Design for a Terahertz Tri-Mirror CATR with High QZ Characteristics

Area of Science:

• Electromagnetics and Optics
• Antenna Measurement Systems
• Terahertz Technology

Background:

• Compact antenna test ranges (CATRs) are crucial for antenna measurements.
• Miniaturization of terahertz CATRs presents challenges in maintaining performance and reducing spatial footprint.
• Existing designs often struggle with cross-polarization and quiet-zone (QZ) field uniformity.

Purpose of the Study:

• To propose and validate a miniaturized terahertz tri-mirror CATR design.
• To achieve low cross-polarization and high-quality QZ characteristics in a compact system.
• To demonstrate the practical engineering potential of the developed CATR.

Main Methods:

• Utilized cross-polarization cancelation via beam mode expansion for geometric configuration.
• Synthesized shaped mirrors using dynamic ray tracing (geometric optics) and dual-paraboloid expansion.
• Optimized QZ field width, feed-edge taper, and incorporated rolled-edge structures to mitigate diffraction.

Main Results:

• Simulated QZ: cross-polarization < -40 dB, amplitude ripple < 1.6 dB, phase ripple < 10°, usage ratio > 70% (100-500 GHz).
• Measured QZ (183 & 275 GHz): amplitude ripple < 1.8 dB, phase ripple < 15°, meeting CATR criteria (< 2 dB, < 20°).
• Achieved a compact system size of 0.61 m × 0.2 m × 0.66 m.

Conclusions:

• The proposed miniaturized terahertz tri-mirror CATR design successfully enhances QZ characteristics.
• The design significantly reduces the spatial footprint, making it suitable for practical engineering.
• This methodology offers a viable solution for compact, high-performance terahertz antenna testing.