This paper presents a bandpass filter design based on a Substrate Integrated Waveguide (SIW) with resonant elements on both sides of the substrate. The proposed filter achieves a unique 0.5 GHz bandwidth centered at 6.54 GHz as well as demonstrates exceptional performance with a Voltage Standing Wave Ratio (VSWR) below 2, ensuring efficient power transmission. Additionally, the filter showcases a rejection level of more than 20 dB for out-of-band frequencies, highlighting its superior selectivity. The novelty of this work lies in the innovative combination of compact size, high-frequency selectivity, and excellent VSWR performance, making it a standout solution for microwave and RF applications. By presenting comprehensive numerical and experimental results, including a detailed comparison with existing designs, this study underscores the significant advancements and advantages offered by the proposed filter in terms of size, frequency response, rejection level, and VSWR optimization.

For upcoming smartphones, a high isolation 4-element multi-input multi-output (MIMO) array antenna operating in the 680 MHz band (3.15–3.83 GHz) is suggested. This is where the n78 band shines, delivering a next-generation wireless internet experience by striking a balance between coverage and speed. In this case, a unique balanced hexagonal ring-shaped antenna with square shaped defected ground is created as an array antenna element. This type of antenna can produce a balanced slot mode that improves the isolation between two adjacent input ports by reducing ground effects. Additionally, desirable polarisation diversity can be successfully achieved by carefully placing the four antenna elements, which further reduces the coupling between antenna elements. The antenna's total dimension is 48 x 48 mm2. A model was produced to verify the simulation. Throughout the intended operation bandwidth, measurements were made to ensure good impedance matching high isolation (> 19 dB), high total efficiency (> 75%), and low envelope correlation coefficient (ECC, < 0.015).  The proposed method is expected to be very beneficial in creating a practical high-performance MIMO antenna concerning parameters such as efficiency, realised gain, mean effective gain (MEG), and total active reflection coefficient (TARC). 

An omni-directional wideband L-shaped patch antenna with an inset feed is designed and tested for sub-6GHz wireless applications. Excitation of the antenna is given through a 50? feed line. Initially, a L-shaped patch antenna is designed with a full ground copper plane and then after partial ground plane has been utilized to attain wider bandwidth. The overall size of the antenna is 40x40x1.575 mm³ and to validate the antenna, it is fabricated by using Rogers/RT duroid 5880. Parametric analysis is done by utilizing Ansys HFSSv13. Fabrication of the antenna is done by using chemical etching. MS2037C Anritsu Combinational Analyser has been used to obtain the measured results of return loss, gain, VSWR and radiation patterns. The simulated L-shaped patch antenna exhibits resonance at 3.1GHz-4GHz with S₁₁ of -25.1dB with a gain of 3.67dBi. The simulated results are in good agreement with the measured antennas results and it is well suited for N77 and N78 sub-6GHz applications.

This paper presents a pioneering Ultra-Wideband (UWB) flexible antenna design utilizing a modified leaf-shaped microstrip patch configuration, specifically designed for wearable applications. The antenna is designed and fabricated using a flexible polyester substrate. The antenna showcases exceptional performance metrics. The radiation efficiency of the proposed antenna, which achieves 94.73%, has a reflection coefficient of -59.8 dB and a gain of 4.2 dB. This innovative antenna design, coupled with the flexible polyester substrate, meets the escalating demand for slender and cost-effective antennas in contemporary wireless communication. Its potential applications span across various domains, including healthcare, IoT devices, and beyond, promising significant advancements in wireless communication systems. 

This study explores highly efficient wave-guide detectors for Si/SiGe lasers utilizing Si1-x-y GexCy. By precisely tailoring properties such as temperature, structure, composition, thickness, and doping, we aim to reduce light losses and im-prove performance by increasing light overlap with the active region. This approach overcomes Si/SiGe lattice mismatch limitations, especially in medium and high germanium SiGe. Incorporating carbon (C) into Si1-x-y GexCy enables perfect light detection and improved confinement, addressing a major challenge in diode lasers. The proposed de-tector design comprises an active zone sandwiched between lightly doped silicon layers (Si(n) and Si(p)) and heavily doped confinement layers (Si1-xGex (n+) and Si1-xGex (p+)). We study three Si1-x-y GexCycompositions (Si0.675Ge0.3C0.025, Si0.74Ge0.25- C0.01 and Si0.79Ge0.2C0.01) with absorption wave-lengths of 1.42 µm, 1.35 µm, and 1.29 µm, respec-tively, and active layer thicknesses ranging from 150-600 nm. For each design, we propose an op-timized waveguide structure with appropriate do-ping.