Vol.:(0123456789) Wireless Personal Communications https://doi.org/10.1007/s11277-019-06628-z 1 3 Design of a Modifed Wilkinson Power Divider with Size Reduction and Harmonics Suppression using Triangle‑Shaped Resonators Masoud Heydari 1  · Parastoo Rostami 1  · Saeed Roshani 2 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract In this study, a miniaturized microstrip Wilkinson power divider (WPD) with harmonic elimination using low pass flter is proposed. In proposed design, two large conventional quarter wavelength transmission lines are replaced with compact low pass flters. Applied low pass flters are consisted of three triangle resonators, which result in harmonics sup- pression and size reduction of the proposed WPD. The proposed WPD has 56% size reduc- tion compared to the conventional one. The proposed divider correctly works at 2 GHz and suppresses second to eighth harmonics with more than 20 dB attenuation level. According to the experimental results the insertion loss of the proposed design is less than 0.1 dB n pass band. The return losses at all ports and output ports isolation parameters are bet- ter than 20 dB and 26 dB, respectively, which shows good performance of the proposed device. Keywords Wilkinson power divider (WPD) · Triangle-shaped resonator · Harmonic suppression 1 Introduction One of the widely used device in the modern wireless circuits and systems is Wilkinson power divider (WPD). Input signals are divided by WPDs into two or more signals [1–3] and used in many systems such as antenna arrays, power amplifers, feeding networks. A conventional WPD, consists of two quarter wavelength (λ/4) lines and a 100 ohms isolation resistor between two lines. Relatively large size and presence of unwanted harmonic in the frequency response are the main drawbacks of the conventional divider. So far, various methods are used to sup- press unwanted harmonics and decrease the circuit size. In [4] by using a π type structure, * Saeed Roshani s_roshany@yahoo.com 1 Young Researchers and Elite Club, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran 2 Department of Electrical Engineering, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran