Miniaturized Dual-Mode Resonators With Minkowski-Island-Based Fractal Patch for Wlan Dual-Band Systems

Abstract

The miniaturized dual-mode dual-band band-pass filters (BPF) using Minkowski-island-based (MIB) fractal patch resonators are proposed in this paper. The BPF is mainly formed by a square patch resonator in which a MIB fractal configuration with 2nd order iteration is embedded in the patch. By perturbation and interdigital coupling, the wide-band and dual-band responses are obtained respectively. For miniaturized wide-band design, at 2.41 GHz central frequency it has good measured characteristics including the wide bandwidth of 2.26-2.56 GHz (3-dB fractional bandwidth of 12.4%), low insertion loss of 0.72 dB, high rejection level (−52.5/−44.9 dB), and a patch size reduction with 60.6%. For compact dual-band design, the proposed filter covers the required bandwidths for WLAN bands . The patch size reduction of 78.1% is obtained. Two transmission zeros are placed between the two passbands and resulted in good isolation.

Inter-digital coupled dual-mode patch resonator with crossed-island configuration for tri-band filter design

“…Analogized to the slot etched resonator , the crossed‐line patch resonator is proposed at first. Then, merged the crossed‐line patch resonator and the MIB fractal resonator , the crossed‐island patch resonator is obtained for improving the MIB fractal resonator. The dimensions of the square patch resonators are: (a) original patch: L 1 = 8.7mm, L 2 = 1.2mm, W 1 = 5.0mm, W 2 = 2.5mm, W 3 = 0.35mm,W 4 = 0.1mm, g = 0.1mm, and W p1 = W p2 = 1.45mm. (b) crossed‐line patch: L 1 = 8.7mm, L 2 = 2.4mm, W 1 = 3mm, W 2 = 2mm, W 3 = 0.5mm, W 4 = 0.2mm, W 5 = 0.25mm, W 6 = 4.38mm, W 7 = 3.09mm, g = 0.1mm, and W p1 = W p2 = 1.45mm (c) crossed‐island patch: L 1 = 8.7mm, L 2 = 4.0mm, W 1 = 3mm, W 2 = 2mm, W 3 = 0.3mm, W 4 = 0.25mm, W 5 = 0.26mm, W 6 = 4.36mm, W 7 = 3.08mm, W 8 = 0.9mm, W 9 = 0.9mm, g = 0.2mm, and W p1 = W p2 = 1.8mm. …”

“…Dual‐mode filters have been widely used in wireless communications systems because of their advantages in applications such as small size and low loss . There are several commonly used dual‐mode patch resonators including crossed slots , loaded crossed‐slots , right crossed‐slots , slot etched , and fractal configurations in a square patch. The arc‐oriented slot etched into a circular patch was used to design a dual‐mode dual‐band BPF .…”

Miniaturised microstrip bandpass filters based on Moore fractal geometry

“…In some techniques, the fractal geometry constitutes the whole microstrip filter structure producing the two resonant bands (Ahmed, 2012;Chen & Lin, 2011;Ghatak et al, 2013;Mezaal et al, 2013b). However, the dual-band resonant response has been reported to be produced using two fractal structures; each contributes to excite one of the resonant bands (Liu et al, 2012). In other techniques, the dual-band resonant response has been produced using a hybrid structure composed of two substructures: one is fractal and the other is non-fractal (Alqaisy et al, 2013).…”

“…Fractal geometries have also been adopted to design compact dual-band BPFs using a variety of techniques as recently reported in the literature (Ahmed, 2012;Chen & Lin, 2011;Ghatak et al, 2013;Liu et al, 2012;Mezaal et al, 2013b). In some techniques, the fractal geometry constitutes the whole microstrip filter structure producing the two resonant bands (Ahmed, 2012;Chen & Lin, 2011;Ghatak et al, 2013;Mezaal et al, 2013b).…”

“…Since then, research work in this field has shown a dramatic increase. In this respect, various fractal geometries have been applied to design compact single-band and dual-band microstrip BPFs (Ahmed, 2012;Alqaisy, Ali, Chakrabarty, & Hock, 2013;Barra, 2004;Chen & Lin, 2011;Chen, Weng, Jiao, & Zhang, 2007;Crnojevic-Bengin, Radonic, & Jokanovic, 2006;Feng, Ming, & Hui, 2012;Ghatak, Pal, & Sarkar, 2013;Li et al, 2012;Liu, Chien, Lu, Chen, & Lin, 2007;Liu et al, 2012;Mezaal, 2009;Mezaal, Eyyuboglu, & Ali, 2013a, 2013b.…”