A compact four-port Ultra-Wideband (UWB) MIMO antenna operating over the 24–42.5 GHz band for millimeter-wave 5G applications is proposed. The antenna is implemented using four rectangular microstrip elements on a Rogers RT/Duroid 5880 substrate with dimensions of 31 × 22 × 0.8 mm³. The novelty of this work lies in the integration of a cross-neutralization line structure to enhance isolation between closely spaced elements without increasing design complexity while maintaining compact size and wide impedance bandwidth. The proposed antenna achieves mutual coupling below -21.2 dB, an Envelope Correlation Coefficient (ECC) less than 0.004, and a diversity gain of approximately 9.99 dB. In addition, it exhibits high radiation efficiency up to 90% and a peak gain of 7.82 dBi. These results demonstrate that the proposed design provides an efficient trade off between compactness, bandwidth, isolation, and diversity performance applications. 

Using the originality of additive manufacturing, which is 3D printing, this study explores the feasibility of utilizing Polylactic Acid (PLA) as a substrate material for Sierpinski carpet antenna development. The proposed antenna design demonstrates superior performance, including enhanced bandwidth and miniaturization. The antenna is fabricated on a PLA substrate with a dielectric constant of 2.68 and a loss tangent of 0.0034, and has a patch dimension of 40×31×1.6 mm3. This antenna has an S11 of –17.83 dB (measured) and –32.04 dB (simulated), a gain of 6.22 dB (simulated) and 5.82 dB (measured), and a peak radiation efficiency of 77% at 2.45 GHz. The design employs 80% concentric infill density, yielding a compact footprint of 1240 mm², which is a 22.87% reduction relative to the zeroth-order iteration. Unlike established Sierpinski carpet antennas on commercial microwave laminates (e.g., Teflon ?r = 2.1, Rogers RO4350 ?r = 3.48), this PLA based approach biodegradable exploits thermoplastics low-cost for and rapid prototyping. A comparative analysis with previous fractal antennas reveals significant advancements. This work represents the first exploration of the Sierpinski carpet fractal geometry on a 3D-printed substrate, with simulated and experimental results demonstrating remarkable agreement. 

The design and analysis of a reconfigurable multilayer cylindrical cloak composed of tunable  isotropic dielectric shells is presented. The formulation is based on the cylindrical Mie scattering theory chosen for TMz_polarization which enforces Maxwell boundary conditions at every concentric interface. A bias-controlled permittivity model enables dynamic tuning of the cloak response without changing geometry. Near-field distributions (incident, scattered, and total fields), internal fields within the cloak and core, and angular far-field radar cross section (RCS) are computed directly from the modal scattering coefficients. This approach can be efficient and suitable for optimization and reconfiguration studies. Results demonstrate substantial scattering suppression at the targeted frequency of  1 GHz.

Substrate Integrated Waveguide (SIW) based volumetric microstrip patch antennas play a vital role in antenna miniaturization while ensuring high performance. In this work, low-profile volumetric SIW antenna is proposed to achieve a single band response. The antenna dimensions are 38.5 × 38.5 × 1.6 mm³, implemented on an FR4 substrate with a microstrip line feed. Detailed parametric analysis was carried out and both simulated and measured results are presented. The proposed design resonates at 7.05GHz and achieves a peak gain greater than 6 dB, confirming its suitability for C-band applications. To enhance predictive design capability, a Random Forest Machine Learning (ML) model was integrated into the workflow. The model achieved high accuracy in resonant frequency prediction (R² = 0.99, RMSE = 0.03) and moderate accuracy in gain prediction (R² = 0.48, RMSE = 0.13 dB). After calibration, the ML predictions closely aligned with the measured descriptors of the fabricated prototype. These results validate the effectiveness of ML-integrated modeling in capturing antenna performance trends and improving prediction reliability. This work presents a complete pipeline: design to simulation to fabrication to measurement to ML calibration.  

A first order compact wideband BPF is designed and analyzed for uplink DBS satellite communication applications. Order of the BPF is analyzed by adding the number of resonators to the pair of transmission lines. First order BPF is designed by utilizing An-soft HFSSv13 and it is manufactured by utilizing chemical etching and the output parameters are measured by utilizing combinational analyser (MS2037C Anritsu). First order BPF is basically a three-layered structure, top layer contains the resonating element, middle layer is the substrate material i.e., FR4 and the bottom layer is the conducting ground layer. H-shaped BPF is designed by cascading the coupled transmission lines. H-shaped BPF occupies an area of 5 x 10 x 1.6 mm³. Reflection coefficient of -17.1 dB has been observed at 12 GHz with an FBW of 11.6% (11.256 GHz-12.62 GHz). Transmission coefficient of <3 dB and group delay of 0.46 nS has been observed at 12 GHz. Close match between the simulated and fabricated results has been observed and these results make the BPF suitable for uplink DBS satellite communication applications.

In this paper, band-pass filters are designed using different combinations of complementary split-ring resonators (CSRRs) and split-ring resonators (SRRs). Four different structures of band pass filters are proposed by placing the CSRR on the ground plane and the SRR are placed on the signal line. The design and simulation of the proposed structure have been carried out by using the HFSS FEM tool. All the performance characteristics of the band-pass filters are studied, such as resonance frequency, bandwidth, and insertion loss. By comparing all the performance characteristics of the proposed structures, the better structure is finalized. The circuit performance of the optimized structure studied with the help of the ADS FEM tool and compared at both the device level and circuit level simulations. There is good agreement between both circuit and device-level simulations.  In the proposed four different structures design-2 show excellent performance characteristics, such as bandwidth, insertion losses and resonance frequency are 2.6 GHz, -30.4 dB and 64.5 GHz respectively. The proposed design -2 is most suitable for millimeter wave applications.