This paper introduces a straightforward method for designing a tri-band bandpass filter using a loaded symmetrical dual-step Impedance Resonator (D-SIR) structure, augmented by multiple open and short circuit stubs. The resulting filter operates at 2.2, 7.9, and 14.1 GHz, showcasing high-band selectivity. Experimental measurements confirm six transmission zeros and six transmission poles across the passbands, yielding fractional bandwidth (FBW) of 42.6%, 63.8%, and 27.9%. Particularly noteworthy is the broader upper stopband rejection, enhancing the filter’s overall performance. The design achieves impressive performance metrics, with minimal insertion loss (IL) of 0.71 dB, 0.87 dB, and 0.76 dB, accompanied by substantial return loss (RL) of 23 dB, 18 dB, and 13.8 dB across the three passbands. Furthermore, the fabricated design have a compact size of (0.20×0.15)λg on a Rogers Duroid RT/5880 substrate. Remarkable agreement between measured and simulated results underscores its viability for IoT-based communication systems.

This paper presents a compact novel pentaband bandpass filter using a dual path stub loaded step impedance resonator (SLSIR). The proposed topology consists of a dual path λ/4 and 2λ/3 long uniform impedance resonator centered separated by 2λ/3 open and λ/12 short circuit stubs respectively. The superposition of signals from the two transmission routes results in a fifth-order pentaband bandpass response with six finite frequency transmission zeroes and out-of-band rejection of 11dB from 12 GHz up to 20 GHz. The filter produces five frequency bands at 1.06 GHz, 3.24 GHz, 5.36 GHz, 8.55 GHz and 10.78 GHz with fractional bandwidth (FBW) of 25.59%, 22.22%, 19.48%, 16.03% and 17.17% respectively. The proposed design is fabricated on a high-frequency substrate with a physical size of (0.23λ _g × 0.14 λ _g ). The new pentaband bandpass filter has a simple and compact design with good electrical performance. A fair match can be found between the simulated and experimental results.

This article presents the design of a wideband bandstop RF filter intending to improve selectivity and compactness. Conventional bandstop filter topology with finite unloaded quality factor produces degraded bandstop filter performance due to dissipation loss. In the proposed filter design, a novel dual path Capacitive Coupled Step Impedance Resonator (CCSIR) structure is used to obtain an infinite stopband attenuation. A uniform impedance resonator is used in Path 1, whereas Path 2 contains a resonator that is twice coupled to the transmission lines. The electrical length of both paths is chosen to be out of phase, resulting in a high rejection level at higher frequencies. It has been analyzed that the selectivity can be improved by increasing the order of the dual coupled step impedance resonator. The proposed design produces a wideband BSF centered at 5.25 GHz with a high rejection level of 104.3 dB and fractional bandwidth of 58.5%. The results have demonstrated that the resonant frequencies are regulated by varying the electrical length of CCSIR. Moreover, it has been realized that out of phase signal cancellation due to the dual path is involved in producing the finite frequency transmission poles, which further enhances the filter selectivity. However, the same electrical performance can only be achieved from coaxial cavities and waveguides due to the high-quality factor. The proposed topology is fabricated and measured on a high-frequency microstrip substrate having a low-quality factor with a compact output and better electrical performance compared to coaxial cavities or waveguides. Due to its high electrical performance and small size, the proposed BSF is appropriate for 4G and 5G (FR1) applications. The measurement shows good concurrence with the full-wave EM simulated results. The fabricated prototype of third order BSF has a compact size of (0.7 × 0.77)λ_g at 5.25 GHz.

This paper presents a multi-mode resonator (MMR) for next-generation wireless systems that achieves single and dual-band bandpass filter (BPF) responses using a split-ring dual-path structure. The proposed BPF design is realized by employing two pairs of parallel couple lines and two symmetrical step-impedance open-circuited stubs (SIOCS). SIOCS are used to improve selectivity and increase the number of transmission zeros/poles. The proposed single-band BPF exhibits an ultra-wideband (UWB) response having a center frequency of 7.5 GHz, a minimum insertion loss of less than 0.48 dB, and a maximum return loss of 25.35 dB. The proposed UWB BPF has a stopband suppression of 39.34 dB up to 18 GHz and a 3 dB fractional bandwidth of 48.23%. Moreover, a dual-band BPF has been accomplished by utilizing the same architecture while slightly changing the MMR structure and adding more coupling. The center frequency (bandwidth) of the dual broadband BPF is 7.40 GHz (2.40 GHz) and 14.15 GHz (1.7 GHz), respectively. The measured minimum insertion loss is less than 0.23 dB and a return loss of less than 16.8 dB with 3 dB FBWs of 32.4 and 12.1%. Finally, two prototypes are fabricated to validate the proposed characteristics. The BPF's simulated and measured results are in good agreement.

As we know, the world is rapidly moving towards 5G and B5G technology to achieve high data rates, massive communication capacity, connectivity, and low latency. 5G offers a latency of less than 1 ms and extremely high data volume compared to previous technologies. The main challenge is the complex nature of 5G network deployment, especially at high frequencies (3–300 GHz) on a university campus with varied building structures. In this paper, we will discuss a scenario for deploying 5G at the Mirpur University of Science and Technology (MUST) in Mirpur, Pakistan so that telecom operators and vendors who wish to deploy a 5G network on the campus in the future can draw on our research findings. This article aims to optimize RF planning for enhanced network performance using Altair WinProp for modeling and MATLAB for visualization. RF planning on campus is conducted to propose equipment for 5G deployment, considering environmental impact, socio-economic perspective, spectral efficiency, electrical effectiveness, and latency in the user project. This helps to identify key base station locations, analyzes path loss and field strength, and shows how high-frequency millimeter waves interact with real-world structures.

In this paper, a miniaturized dual-band bandpass filter (DB-BPF) based on a dual-path stub-loaded resonator is presented. A transversal filtering design is introduced in the proposed DB-BPF, which provides two signal propagation paths from input to output. In total, six transmission poles and four transmission zeros are obtained, which improves overall filter selectivity. The fractional bandwidth (FBW) of dual bands with center frequencies of 2.24 and 7.35 GHz is 36.4% and 31.2%, respectively. The physical size of a fabricated filter is $(0.43\ \times 0.17)\lambda_{g}$ , where $\lambda_{g}$ is the guided wavelength at 2.24 GHz. The DB-BPF prototype is fabricated using a Roger Duroid RT/5880 substrate to further validate the result. The full-wave EM simulation and measured results show good agreement. The proposed dual-band bandpass is applicable to a wide range of modern communication technologies, including Wi-Fi, satellite, cellular, radar, and broadcast communication.