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Microstrip antenna with reflector and air gap for short range communication in 900 MHz band Shairi, Noor Azwan; Zakaria, Zahriladha; Mohd Ibrahim, Imran; Osman, Anwar Faizd
Bulletin of Electrical Engineering and Informatics Vol 13, No 2: April 2024
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v13i2.5515

Abstract

This paper proposes a microstrip antenna that was made of a microstrip fed slot with a complimentary stub on a single dielectric medium. This antenna was integrated with a reflector and air gap for the application of short range communication (SRC) in a 900 MHz band. Analyses were made on the dimension of the reflector and the height of the air gap towards the antenna performance. Besides, an antenna field test was done for the propagation distance of the proposed antenna. As a result, with the antenna size of 13,770 mm2 , the measured return loss was -10.79 dB and the directivity gain was 7.44 dBi. Besides, with the effective isotropic radiated power (EIRP) of 7.44 dBm, it was predicted that at 100 m, the received signal would be around 60 to 70 dBm. Therefore, a high gain was produced by using a reflector with air gap and a compact size was achieved if compared to conventional high gain antenna designs such as Yagi Uda. Thus, it is suitable for a communication device such as the SRC application.
High isolation of SPDT PIN diode switch using switchable dumbbell-shaped DGS in millimeter wave 28 GHz band Mohd Yasin, Fatin Nadiah; Shairi, Noor Azwan; Othman, Adib; A. Majid, Huda; Zakaria, Zahriladha; Mohd Ibrahim, Imran; Jamaluddin, Mohd Haizal
Bulletin of Electrical Engineering and Informatics Vol 12, No 6: December 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v12i6.6071

Abstract

This paper proposes a high isolation of single pole double throw (SPDT) PIN diode switch using switchable dumbbell-shaped defected ground structure (DGS). The proposed SPDT switch was designed for radio frequency (RF) front-end transceiver of antenna array multiple input multiple output (MIMO) in millimeter wave 28 GHz band. The switchable dumbbell-shaped DGS can be switched between allpass and bandstop responses where the bandstop response of the DGS can be utilized as a high isolation in the SPDT PIN diode switch circuit. A simple mathematical analysis is explained in this paper for the bandstop and allpass responses of the switchable dumbbell-shaped DGS. The propose SPDT switch was designed based on Roger RT/Duroid 5880 with 0.254 mm thickness and relative dielectric constant of 2.2. The simulated result showed that the proposed SPDT PIN diode switch produced an isolation of 36.36 dB at 27.3 GHz (center of 28 GHz band), which was 63% higher than the conventional SPDT design.
Performance Comparison of UWB Single Balanced Schottky Diode Mixers for RF Front-End Applications in 3-10 GHz Band Shairi, Noor Azwan; Mohammed , Yahya Al-gumaei; Zakaria, Zahriladha; Maizatul Alice Meor Said; Misran, Mohamad Harris; Abdullah Mohammed, Zaghir Zobilah
Advance Sustainable Science Engineering and Technology Vol. 7 No. 2 (2025): February-April
Publisher : Science and Technology Research Centre Universitas PGRI Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26877/jsy73y58

Abstract

This paper compares two single balanced mixer designs for ultra-wideband  (UWB) of RF front-end at frequencies ranging from 3 to 10 GHz. The proposed mixer designs use two balun topologies for varying mixer performances. Thus, Design 1 incorporates a Coupled Line Balun and Design 2 incorporates a Branch Line Balun. Both designs make use of Skyworks' SMS7621 Schottky diodes, which have a low junction capacitance, and the Rogers RO4350B substrate, which has a dielectric constant of 3.48. The Coupled Line Balun (Design 1) offers a total length of 88 mm, whereas the Branch Line Balun (Design 2) creates a more compact structure with 48 mm. This paper's thorough analysis and measurements show each design's benefits and drawbacks in terms of circuit size and performance. The simulations and measurement results of both designs generally showed a conversion loss of less than 20 dB and LO-RF isolation of better than 50 dB.
Design of Wideband SPDT RF Switch Using Switchable DGS for Sustainable Wireless Systems Othman, Adib; Shairi, Noor Azwan; A Majid, Huda; Saparudin, Faiz Asraf; Zakaria, Zahriladha; Najib Al-Fadhali
Advance Sustainable Science Engineering and Technology Vol. 7 No. 4 (2025): August-October
Publisher : Science and Technology Research Centre Universitas PGRI Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26877/asset.v7i4.1957

Abstract

This paper presents a single-pole double-throw (SPDT) switch that is integrated with a thin rectangular patch switchable defected ground structure (DGS). It is a novel technology for obtaining wideband and high isolation for the SPDT switch in millimeter-wave (mm-wave) telecommunications due to the usage of switchable DGS with bandstop and bandwidth enhancement capabilities. A wideband and high isolation are required for the switchable DGS SPDT switch to operate optimally in mm-wave frequency ranges, as well as to reduce the effect of leakage signal on both the transmitter and receiver connected to the SPDT switch and hence improve system efficiency and signal integrity. The SPDT switch design was combined with two small rectangular patches switchable DGSs that could switch between bandstop and allpass responses using biasing diodes on the DGS. As a result, the suggested SPDT switch with the switchable DGS had 6 dB of insertion loss and high isolation of more than 25 dB with wideband isolation of 25.24% fractional bandwidth, which was consistent with the simulation results. Furthermore, the isolation magnitude is doubled compared to the conventional SPDT switch. This work demonstrates that integrating switchable DGS into discrete SPDT switches provides a practical solution for realizing wideband, high-isolation performance suitable for 5G mm-wave where compactness and bidirectional reconfigurability is increasingly essential for sustainable RF front-end systems.