Designing a Compact Filtering Quasi-Yagi Antenna with Multiple Radiation Nulls Using Embedded Resistor-Loaded Arms

Area of Science:

• Electrical Engineering
• Electromagnetics
• Antenna Theory

Background:

• Filtering antennas are crucial for modern wireless communication systems to mitigate interference.
• Quasi-Yagi antennas offer directional radiation but often lack inherent filtering capabilities.
• Achieving compact filtering antennas with multiple radiation nulls remains a design challenge.

Purpose of the Study:

• To propose a compact quasi-Yagi antenna with embedded resistor-loaded arms.
• To achieve a filtering response with four distinct radiation nulls.
• To demonstrate the antenna's performance in the 5G N78 band.

Main Methods:

• Designing a quasi-Yagi antenna structure incorporating resistor-loaded arms.
• Utilizing reverse currents and absorption by resistor-loaded arms to create radiation nulls.
• Integrating a balun and fabricating a prototype for experimental validation.

Main Results:

• The proposed antenna exhibits a filtering response with four radiation nulls.
• A compact endfire size of 0.13 free-space wavelengths (λ0) was achieved.
• The prototype demonstrated a 22.9% impedance-matching bandwidth (3.21–4.04 GHz) and a peak gain of 4.73 dBi.

Conclusions:

• The embedded resistor-loaded arms effectively generate additional radiation nulls and absorb unwanted resonances.
• The compact filtering quasi-Yagi antenna provides a superior solution compared to existing designs.
• The demonstrated performance in the 5G N78 band validates the antenna's practical applicability.