Design and fabrication of a Wilkinson power divider with harmonic suppression for LTE and GSM applications

Abstract

Conventional Wilkinson power dividers (WPDs) can provide acceptable performance close to the nominal center frequency. However, these WPDs can also exhibit poor out-of-band performance while requiring a large footprint. In order to improve on the current state of the art, a modified microstrip WPD is proposed that exhibits a substantially improved stopband and high isolation. A lowpass filter (LPF) structure is utilized in both branches of the power divider to provide harmonic suppression. According to the obtained results, the input return loss (|S11|), output return loss (|S22|), output insertion loss (|S21|) and isolation (|S32|) are better than 34.2 dB, 26.2 dB, 3.52 dB and 31.2 dB, respectively. The proposed modified WPD has a wide 20 dB stopband (from 2.54 GHz to 13.48 GHz) and filters the second to seventh harmonics with attenuation levels of greater than 20 dB. The proposed WPD has a small size of 33.8 mm × 27 mm (0.42 λg × 0.33 λg), where λg is the guided wavelength at the operating frequency of 1.8 GHz. The WPD has been fabricated and tested and shows good agreement between simulated and measured results and the proposed design has desirable characteristics for LTE and GSM applications.

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

“…Aiming for a higher Roll-of-rate (ROR), the conventional resonator was modified. These modifications manipulate the distributed surface current and electrical field and improves the frequency response of the conventional resonator 44 . The new design structure illustrates better response (sharper ROR and higher SF) than the previous structure.…”

“…8 . To achieve an accurate LC equivalent circuit, the meandering lines in the layout of the modified resonator have been modelled by a π-type circuit according to the reference 44 . Apart from the modelling approach used here, there are other techniques based on modal analysis 46 , artificial intelligence-based approaches 47 and transfer functions 48 , 49 .…”

“…With the rapid growth of technology in recent decades, the need to expand and upgrade wireless communication devices has increased dramatically. According to modern comprehensive needs to improve quality and the need for higher speed in wireless communication, special attention has been paid to increasing the quality and upgrading active and passive microwave devices such as antennas 1 – 5 , filters 6 – 18 , multiplexers 19 – 24 , and power dividers 25 – 44 . Power divider plays a vital role in modern microwave devices.…”

“…The demand for multi-port components, such as diplexers 19 – 24 and power dividers 25 – 44 has been experiencing significant growth in contemporary communication systems. Indeed, by integrating filters with power dividers and diplexers, more desirable features such as increasing the stopband, improving suppression bandwidth to eliminate unwanted harmonics and reducing the size and footprint can be achieved.…”

“…Recently, several techniques and topologies for designing filtering power dividers, such as squared resonator based on artificial intelligence 26 , 27 , microstrip open and short stubs 28 , high/low impedance ring resonators 29 , 40 , 42 , open complementary split-ring resonator 30 , capacitor loading 31 , square-loop resonator and meandered stubs 32 , parallel strip line and DGS 34 , hexagonal shaped resonator and multi open stubs 35 , radial resonator and multi open stubs 36 , 37 and microstrip electromagnetic bandgap element 43 have been reported. However, a modified WPD with LPF structure and high isolation has been presented in 44 , the footprint is a bit large. In the cutting-edge next-generation communications, the design of a WPD that offers miniaturisation, harmonic suppression, high isolation, wide stopband performance, sharp ROR, high SF, and low-cost implementation remains a challenge at present.…”