Browsing by Author "Herceg, Lamija"

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Microstrip Filters Based on Open Stubs and Sir for High Frequency and Ultra-Wideband Applications
(Academic Publication Council, 2022) TahaImeci, S.; Tutuncu, Bilal; Beslija, Faruk; Herceg, Lamija
This paper includes two new microstrip filter configurations for high frequency and ultra-wideband applications. The first proposed filter is a composition of four parallel open-circuited stubs connected by optimized fractal-structured microstrip line. The filter response is a combination of three passing regions, namely, low pass from 0.1 GHz to 3 GHz, band-pass from 4.5 GHz to 9 GHz, and high pass from 10.5 GHz to 13 GHz, separated by two rejection regions from 3 GHz to 4.5 GHz and 9 GHz to 10.5 GHz. Deep and sharp rejection regions reaching up to-44.6 dB with 40 % fractional bandwidth (FBW) are observed with a good electrical performance. Furthermore, with a comparative table, the advantages of this proposed BSF in terms of FBW, compactness, and insertion loss are compared with recently reported related studies. Secondly, a dual -band band-pass filter implementing a stepped-impedance resonator (SIR) and a modified H-shaped structure is presented. This filter is designed to operate in a low pass region up to 3.58 GHz and a band-pass region from 15.38 to 21.65 GHz, with a wide stopband region between 4.46 and 14.07 GHz. The simulated and measured results are in good agreement. Compared to its peers, the compact size and low price allow for a wide application of these filter configurations, while passing frequencies allow operation in the unlicensed frequency spectrum, which is popular for high-speed communication.
Performance-Enhanced S-Shaped Slotted Patch Antenna for X Band/Ku Band Applications
(Springer, 2023) Imeci, S. Taha; Tutuncu, Bilal; Herceg, Lamija
Design and performance enhancement of an S-shaped antenna with two additional slits and slots is presented. Initially, a parametric study was performed with two commonly used dielectric materials. First, FR4 with er = 4.3 and thickness of 1.55 mm was used, followed by RO4003C with er = 3.55 and thickness of 0.8 mm. Suitable for high frequencies, the RO4003C outperforms the affordable but lossy FR4. Thus, the antenna is fabricated with RO4003C. The simulated and measured results are in good agreement. Since the proposed antenna operates at two resonant frequencies, 10 GHz and 17.65 GHz, it is suitable for both X and Ku bands. The better gain was obtained at 10 GHz, with a measured gain of 6.3 dB. Finally, a comparative table is given, which reveals the superiority of the proposed antenna in terms of gain and compactness over some X-band antennas recently presented.