Miniaturized Power Divider With Triple-Band Filtering Response Using Coupled Line

Abstract

This proposed work describes a miniaturized and simple power divider that uses coupled lines for triple-band filtering. The intended setup included an isolation resistor connecting the output feed lines through Structure-3 and coupled line-based microstrip resonators connected to the input feed line. The presented power divider achieves three passbands with a filtering response. The first and second passbands are achieved by the coupled line that includes Resonator-1 and Resonator-2 of the proposed structure. The third passband is realized due to Resonator-3. Furthermore, by varying the structural parameter of the designed triple-band filtering power divider, the resonance frequencies of all three passbands can be controlled because of changes in their equivalent lumped parameters. The resonance frequency mainly depends on its equivalent inductance and capacitance value. For validation of the simulation result, the filtering power divider structure has been fabricated and tested. The experimental results denote that the prototype has a fractional bandwidth (|S21|<-3 dB) of about 20.0 % (1.1 GHz to 1.35 GHz), 37.0 % (2.0 GHz to 2.9 GHz), and 15.0 % (3.25 GHz to 3.8 GHz) respectively for first, second and third pass-bands. This arrangement shows isolation above 18 dB for all three bands with a downsized of 0.1λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>g</i></sub> × 0.12λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>g</i></sub> (25 mm × 30 mm) according to the operating frequency of the first frequency passband. The triple band performance of the developed component shows a good input reflection coefficient. The operating frequencies, which are suitable for the application of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</i> -band, WLAN, sub-6 GHz band of 5G, which include 1.23 GHz, 2.41 GHz, and 3.55 GHz.