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This article discusses the development and analysis of a broadband filter capable of suppressing specific frequencies of wireless applications at 4.7 GHz for WLAN, 8.3 GHz, and 11.5 GHz (for satellite communication) by combining a T-shaped stub loaded resonator with a central square ring to achieves high performance and compact size within the bandwidth of interest. The filter achieves low signal loss of 0.4 dB across the entire passband of 14.9 GHz bandwidth, good reflection suppression exceeding 10 dB, and independently adjustable multi stopbands. It utilizes a simple planar topology for a small footprint of 0.52 λ g × 0.32 λ g , where λ g represents the wavelength at 4.7 GHz. The proposed filter evaluated using classical method an even-odd-mode analysis, and a 3D software tool HFSS-15 is used for simulations. The physical prototype is built on a Rogers RO-4350 substrate using LPKF S63 ProtoLaser machine. To confirm the accuracy and performance of the prototype, measurements were conducted using a ZNB20 vector network analyser. The simulations and measurement results confirm its effectiveness, paving the way for applications in various fields such as radar systems, medical imaging, and wireless communication. [ABSTRACT FROM AUTHOR]

A novel three-mode step impedance resonator (TSIR) is developed to design a miniaturized multi-pole microstrip planar ultra-wideband (UWB) filter with independently controlled notched bands at different frequencies is presented in this work. The basic UWB filter consists of four L-shaped λ/4 short-circuited stubs operating in the range of i.e. 2.7 to 12.1 GHz with fractional bandwidth (FBW) 127%, and the TSIR is constructed using two T-shaped λ/2 open ended step impedance resonator (SIR) and one λ/4 short-circuited uniform impedance resonator (UIR) is coupled to the basic UWB design in order to achieve the stopbands performance at 5.1 GHz, 6 GHz, and 8 GHz, to supress the unwanted bands of WLAN, Wi-Fi 6E, and X-band satellite communication system, respectively. Commercial full-wave electromagnetic (EM) software HFSS-13 was used to design an ultra-compact structure having size 0.07 λg×0.02 λg on Rogers RT/Duroid 5880 substrate to justify good agreement between simulated and measured S-parameters. [ABSTRACT FROM AUTHOR]

A novel miniaturized multiband, single-feed microstrip patch antenna is presented in this paper for WLAN and WiMAX applications. Both size reduction and multiband are obtained by etching the Multiple Complementary Split Ring Resonators (MC-SRR) on the ground plane of the normal patch antenna. At first, the normal patch antenna produces a single band of 5.15 GHz; 200 MHz (5.0500~5.2499). Subsequently, a Single Circular Split Ring Resonator (SC-SRR) is etched on the ground plane and produces a triple band of: 3.25 GHz; 288 MHz (3.1085~3.3964), 4.5 GHz; 101.3 MHz (4.4488~4.5501), and 5.22 GHz; 220 MHz (5.1191~5.3400) and Double Single Circular Split Ring Resonator (DC-MCSRR) with: 2.99 GHz; 60.7 MHz (2.9574~3.0181), 3.57 GHz; 324.7 MHz (3.4065~3.7312), and 5.1413 GHz; 115.4 MHz (5.0817~5.1971). The working bandwidths cover the desired frequency bands of WLAN 5.2 GHz and WiMAX 3.3/3.5 GHz. The proposed (MC-SRR) antenna can be employed to wireless communication systems due to its simplicity in design, compactness and miniaturization. [ABSTRACT FROM AUTHOR]

This paper proposes a four-port, four-element multi-band Multiple-Input Multiple-Output (MIMO) antenna array that resonates at 2.4 GHz, 2.9 GHz, and/or 5.8 GHz frequency bands for WLAN applications. A Complementary Split Ring Resonator (CSRR) was designed on the ground plane of the FR4 substrate with a rectangular patch antenna on the top plane for antenna size miniaturization, bandwidth improvement, compactness, and isolation enhancement. At first, the presence of the CSRR on the conventional antenna creates additional frequency bands and reduces the frequency of the conventional patch antenna from 24.2 GHz to 5.8 GHz. Even though the CSRR as radiating elements are closer to each other at λ/4 in the MIMO design, minimum isolation is achieved by limiting the unnecessary surface current flow that exists between the elements of the antenna. Consequently, an orthogonal method of the antenna element is adopted for the four-port MIMO antenna system with high port-to-port measured isolation of less than −19 dB, −18 dB, and –22 dB for 2.4 GHz, 2.9 GHz, and 5.8 GHz frequency bands respectively. Antenna size reduction of 96.87%, 95.41%, and 81.10% and gain of 3.94 dBi, 3.80 dBi, and 4.08 dBi were achieved for the miniaturized multi-band antenna operating at 2.4 GHz, 2.9 GHz, and 5.8 GHz frequency bands, respectively. The results also provided overall good diversity performances with the ECC < 0.01, DG > 9.98, MEG < 3 dB, and TARC in all of the proposed multi-band MIMO antenna systems at respective frequencies. The reflection & transmission coefficients, surface currents, radiation patterns, total efficiency, and diversity parameters are presented and discussed. Moreover, the proposed integration of CSRR with the antenna for MIMO antenna arrays has the advantage of multi-band operation, size reduction, isolation enhancement, good diversity, and high gain performances. With this, it is possible to conclude that the proposed metamaterial multi-band MIMO antenna is the right candidate for WLAN applications. [ABSTRACT FROM AUTHOR]