A miniatured helical antenna based on the sinusoidal folding structure with exponential spacing

Area of Science:

• Electromagnetics and Antenna Engineering
• Microwave Engineering

Background:

• Conventional helical antennas face limitations in size, bandwidth, and gain.
• Achieving good circular polarization (CP) often conflicts with dimensional reduction in helical antenna designs.

Purpose of the Study:

• To develop a compact and high-performance helical antenna with enhanced circular polarization (CP) characteristics.
• To investigate the impact of exponential spacing and sinusoidal folding on antenna performance.
• To improve gain through the use of a cavity-backed structure.

Main Methods:

• A novel antenna design incorporating exponential helix spacing and a sinusoidal folded structure was developed.
• The helical antenna was backed by an optimized cavity to enhance its gain.
• Performance metrics including dimension, volume, impedance bandwidth, axial ratio, and gain were measured and compared to a conventional helical antenna.

Main Results:

• The proposed exponential spacing and sinusoidal folded helical (ESSFH) antenna achieved a 53% volume reduction compared to the conventional helical (CH) antenna.
• The ESSFH antenna exhibited a significantly wider impedance bandwidth (0.43–1.02 GHz) than the CH antenna (0.48–0.60 GHz).
• The ESSFH antenna demonstrated a lower axial ratio (1.77 vs. 2.61) and 22% higher effective potential gain.

Conclusions:

• The cavity-backed ESSFH antenna design successfully overcomes the limitations of conventional helical antennas.
• The integration of exponential spacing and sinusoidal folding, along with a cavity, leads to substantial improvements in antenna size, bandwidth, gain, and CP characteristics.
• This advanced helical antenna design presents a promising solution for applications requiring compact, high-performance antennas.