| 1. |
- Chomtong, P., et al.
(författare)
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A Miniaturized Multiband FSS Director Using Double Layer With ICPW Technique Structure for Wireless Communication Systems
- 2023
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Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 11, s. 81527-81544
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a multiband director based on the frequency selective surface (FSS) unit cell structure using the double layer with interdigital CPW (ICPW) technique. The unit cell consists of the front and the back. The front part has been designed using an ICPW technique based on a coplanar waveguide structure to enhance the capacitance between the transmission line and the semi-ground. The overall structural dimension of the unit cell can be designed to be smaller than the conventional range of λ/2 to λ/8, due to the influence of the slow wave effect on the capacitance of the structure. The back part is the inverted layer of the front, which alternates between substrate and copper. It is composed of a square loop resonator with a double meandering line. The capacitance generated by a double meander line enhances the capacitance in the front part, which influences the control of all resonant frequencies and increases the slow wave on the double-layer unit cell structure, resulting in a significantly reduced dimension. The resonance frequencies for the designs are 1.8 GHz (LTE), 3.7 GHz (Wi-MAX) and 5.2 GHz (WLAN), respectively. According to simulation results, the FSS can transmit all resonant frequencies. It has an overall dimension of 10.93 mm × 11.48 mm. In addition, the FSS unit cell has been arranged as a 7 × 7 array for use as a director. The dimensions are 73.48 mm × 77.38 mm. The FSS director will be evaluated utilizing an omnidirectional dipole antenna at the same resonant frequency as the FSS unit cell. According to both the simulated and measured outcomes, the impedance matching value is below -10 dB at the three resonant frequencies. The FSS director equipped with a dipole antenna exhibits bidirectional propagation characteristics across all resonant frequencies. The antenna gains for simulation are 3.45 dBi, 3.05 dBi, and 3.72 dBi, while the antenna gains for measurement are 3.05 dBi, 2.98 dBi, and 3.12 dBi. The findings indicate a high level of concurrence.
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| 2. |
- Chomtong, P., et al.
(författare)
-
Dual-Mode Characteristic Based on Miniaturized Metamaterial for Multiband Operation Utilizing Double-Layer Interdigital and Trisection Step-Impedance Techniques
- 2023
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Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 11, s. 126232-126250
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a dual-mode characteristic for miniaturized metamaterial with a unit cell design based on an interdigital coplanar waveguide (ICPW) combined with trisection step-impedance to enable the three resonant frequency responses of 1.8 GHz, 3.7 GHz, and 5.8 Hz. In addition, the unit cell dimensions can be reduced from 2/2 to 2/8 due to the fact that the ICPW technique based on the CPW structure enhances the capacitive load between the transmission line and the side ground, thereby increasing the slow-wave on the transmission line. In addition, the trisection step-impedance will be incorporated and applied to the transmission line and cooperate with the unit cell structure's capacitive load to effectively resonate at the desired frequency location. Moreover, the unit cell structure designed with the method above must be utilized as a double layer in which the structure on both sides is identical. The back structure will property the rod, which will cause the permittivity and permeability to be negative and closer to zero. This property of the proposed material allows for its utilization as a director at its first resonant frequency and as a reflector at the subsequent second and third resonant frequencies. The proposed metamaterial employs FR-4 printed circuit boards with a dielectric constant (epsilon(r)) of 4.4, a substrate thickness of 1.6 mm, a conductor thickness of 0.035 mm, and a loss tangent (tan delta) of 0.04. The unit cell size is approximately 14 mmx14 mm. The unit cell will then be arranged as a 7 x 7 array with an overall dimension of 98 x 98 mm(2) to evaluate an antenna's performance. An antenna used for testing the proposed unit cell is a dipole antenna that propagates at a single frequency corresponding to the unit cell's resonant frequency. At all resonant frequencies, the impedance matching of the dipole is less than -10 dB. At 1.8 GHz, 3.7 GHz, and 5.8 GHz, the dipole antenna gain is 2 dBi, 2.06 dBi, and 1.95 dBi, respectively. Moreover, the dipole antenna's characteristics were simulated using the CST program in conjunction with the unit cell array. Based on the simulation and measurement results, the antenna with the unit cell array exhibits an impedance bandwidth of less than -10 dB at frequencies of 1.8, 3.7, and 5.8 GHz. The gains obtained from the simulation results are 5.49 dBi, 8.21 dBi, and 7.87 dBi, while the measurement results show gains of 5.73 dBi, 8.19 dBi, and 7.79 dBi, respectively. The simulated and measured outcomes demonstrate a substantial correspondence.
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| 3. |
- Chomtong, P., et al.
(författare)
-
Miniaturized Multiband EBG Reflector Using DICPW Structure for Wireless Communication Systems
- 2024
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Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 12, s. 30398-30415
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Tidskriftsartikel (refereegranskat)abstract
- Wireless communication technology evolves to meet current needs, focusing on antenna size reduction for smaller, multi-frequency devices. This research introduces a novel approach to miniaturizing a multiband Electromagnetic Band Gap (EBG) reflector using a Double Interdigitated Coplanar Waveguide (DICPW) structure. The mushroom-patterned EBG unit cell, employing a double interdigital technique based on a Coplanar Waveguide (CPW), achieves a significantly slower wave on the transmission line. The unit cell size can be reduced from lambda/2 to lambda /8, allowing control over the second to fourth resonance frequencies. Engineered for a fundamental frequency of 1.8 GHz (LTE), the proposed EBG unit cell supports frequency ranges of 2.45 GHz (WLAN), 4.3 GHz (Altimeter), and 5.2 GHz (WLAN). Integrating this EBG reflector with a dipole antenna at the same frequency results in directional radiation patterns and gains of 8.29 dBi, 8.76 dBi, 8.55 dBi, and 8.22 dBi at resonance frequencies. The innovative reflector, with improved gain and compact dimensions, is relevant to cube satellite and wireless communication systems with versatile multiband frequency requirements.
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