Broadband sub-array decoupling for tightly coupled arrays to radiate ultrawideband pulses based on...

Area of Science:

• Electromagnetics and Antenna Theory
• Microwave Engineering
• Signal Processing

Background:

• Mutual coupling in ultrawideband (UWB) antenna arrays complicates compact design.
• Conventional decoupling methods are insufficient for the broad frequency range of UWB systems.
• Minimizing gain loss is crucial for maintaining waveform fidelity in UWB pulse radiation.

Purpose of the Study:

• To propose a broadband sub-array decoupling method for two-dimensional (2D) tightly coupled arrays (TCAs).
• To investigate the surface-wave mechanism causing sub-array mutual coupling in TCAs.
• To develop a novel decoupling technique that enhances isolation and bandwidth without significant gain loss.

Main Methods:

• Analysis of sub-array mutual coupling mechanism, identifying surface waves along the sub-array axis.
• Introduction of a resistive decoupling chain (RDC) between sub-arrays to absorb coupling energy.
• Design and fabrication of a 4x8-element TCA loaded with the proposed RDC.

Main Results:

• The RDC significantly reduced sub-array mutual coupling in the developed TCA.
• The operating bandwidth of the TCA was extended to 0.35-3.93 GHz.
• Pulse fidelity in radiating fields reached 0.998, with minimal impact on effective potential and gain.

Conclusions:

• The proposed RDC method achieves broadband decoupling for UWB pulse radiation.
• The technique effectively mitigates mutual coupling without compromising frequency- or time-domain performance.
• This method enables compact TCA designs for UWB applications with high waveform fidelity.