A Novel Mode Fusion, Dual-Broadband Folded Dipole Antenna

This paper presents a dual-broadband antenna with three half-wave modes and one full-wave mode which evolves from a traditional folded dipole. Initially, the author sets up a dual-branch impedance adjustment structure at the center of the traditional folded dipole. The impedance adjustment structure comprises two parallel microstrip lines, which compensate for the large capacitance of the folded dipole. Consequently, the frequency corresponding to the full-wave mode of the folded dipole shifts downward and merges with the half-wave mode of the dipole, achieving coverage of the 2.9∼4.2 GHz band. Subsequently, two rectangular branches of different lengths are added to the impedance adjustment structure, forming two equivalent dipoles that operate in the half-wave mode and generate two resonance points at 2.3 and 2.7 GHz. Finally, the author extends the folded dipole along the narrow side to merge the aforementioned low-frequency resonance points. The antenna can cover the low frequency band of 2.2 ∼ 2.7 GHz and the high frequency band of 3.2 ∼ 3.9 GHz while maintaining high gain within the working frequency band. The antenna boasts a simple structure and wide bandwidth, making it suitable miniaturized communication systems.