Reconfigurable beam-steerable leaky-wave antenna loaded with metamaterial apertures using liquid crystal-based delay...

Area of Science:

• Electromagnetics and Wave Propagation
• Antenna Theory and Design
• Materials Science for RF Applications

Background:

• Substrate Integrated Waveguide (SIW) technology offers planar integration advantages for microwave circuits.
• Leaky-wave antennas provide continuous beam scanning capabilities.
• Liquid crystals (LCs) exhibit tunable dielectric properties, enabling reconfigurable RF devices.

Purpose of the Study:

• To propose and analyze an original liquid crystal (LC)-based substrate integrated waveguide (SIW) leaky-wave antenna.
• To demonstrate fixed-frequency continuous beam steering using LC permittivity tuning.
• To evaluate the antenna's performance metrics, including gain, bandwidth, and robustness.

Main Methods:

• Design of an SIW leaky-wave antenna incorporating an LC-filled stripline resonator.
• Utilizing complementary electric inductive-capacitive (cELC) resonators for coupling the guided mode to free space.
• Applying a quasi-DC bias voltage to the stripline to modulate the LC permittivity.
• Conducting electromagnetic simulations to analyze beam steering range, gain, and bandwidth.

Main Results:

• Achieved a fixed-frequency continuous beam steering range of 52° (from -28° to 24°) at 25.85 GHz.
• Demonstrated wide-angle scanning by tuning the LC permittivity via applied bias voltage.
• Observed high realized gain with minimal degradation (<1 dB) across the scanning range.
• Confirmed relatively wide bandwidth and good tolerance to frequency drift and fabrication errors.

Conclusions:

• The proposed LC-based SIW leaky-wave antenna enables efficient, wide-angle beam steering at a fixed frequency.
• Tunable LC permittivity is an effective method for achieving dynamic beam control in SIW antennas.
• The antenna design shows promise for applications requiring reconfigurable radiation patterns with high performance.