A Wilkinson power divider with harmonic suppression through low-pass filter for GSM and LTE applications

Nariman Mohammadi; Gholamhosein Moloudian; Saeed Roshani; Sobhan Roshani; Fariborz Parandin; Ali Lalbakhsh

doi:10.1038/s41598-024-52506-5

A Wilkinson power divider with harmonic suppression through low-pass filter for GSM and LTE applications

Sci Rep. 2024 Jan 29;14(1):2429. doi: 10.1038/s41598-024-52506-5.

Authors

Nariman Mohammadi¹, Gholamhosein Moloudian², Saeed Roshani³, Sobhan Roshani³, Fariborz Parandin³, Ali Lalbakhsh⁴

Affiliations

¹ Electrical Engineering Department, Salman Farsi University, Kazerun, Iran.
² Tyndall National Institute, University College Cork, Cork, T12R5CP, Ireland.
³ Department of Electrical Engineering, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran.
⁴ Macquarie University College, Sydney, Australia. ali.lalbakhsh@mq.edu.au.

Abstract

Conventional Wilkinson power dividers (WPDs) perform satisfactorily near the intended operation frequency. Nonetheless, these WPDs demonstrate subpar performance in the stopband and necessitate a significant physical space. To enhance the existing level of advancement and in order to improve on the current state-of-the-art, a modified WPD is designed and fabricated, demonstrating a significant improvement in stopband and superior isolation between output ports. To improve the stopband and suppress unwanted harmonics, a low-pass filter (LPF) structure is placed in the both branches of the conventional WPD. The proposed modified WPD depicts a wide stopband bandwidth (f_SB > 17.25 GHz) from 2.75 to over 20 GHz with an attenuation level of 20 dB, suppressing 2nd to 11th harmonics. According to measured results, the input return loss (|S₁₁|), insertion loss (|S₂₁|) and output isolation (|S₃₂|) at f = 1.8 GHz are better than 33 dB, 3.2 dB and 21 dB, respectively. Indeed, the proposed modified WPD exhibits a magnitude imbalance of 0.00018, a phase imbalance of 1.25 degrees and a group delay of 0.5 ns. The proposed WPD depicts a compact size of 35 mm × 25 mm (0.38 λg × 0.27 λg), where λg is the guided wavelength at f = 1.8 GHz. There is a good agreement between the simulated and measured results. According to the obtained results, the proposed modified WPD shows a desirable performance for modern LTE and GSM communication applications.