“…Among the reported resonator structures such as star-shaped ring (Wei and Kewei, 2012), square patch (Yeh et al , 2014; Mezaal et al , 2018; Liu et al , 2019; Cheng et al , 2019; Zhao et al , 2020), octagonal patch (Karthie and Salivahanan, 2019), star-shaped loop (Avinash and Rao, 2017) and hexagonal loop (Song et al , 2017) with different patch/slot as perturbation elements, the proposed square patch resonator with a diagonal square perturbation patch exhibits a compact size of 7.35 × 7.35 mm 2 and a size reduction of 61%, respectively. Amid the filter designs fabricated on RT/duroid 6010 substrate with a relative permittivity of 10.2, the proposed structure offers more miniaturization on the same substrate in addition to the filter designs by Wei and Kewei (2012), Liu et al (2019) and Cheng et al (2019) on different substrates.…”