This paper introduces a compact planar UWB monopole antenna array designed with tri-band notching features. The antenna covers the entire UWB spectrum, ranging from 3.1 GHz to 10.6 GHz. The design includes slots for notching to prevent interference with three unlicensed bands: WiMAX (3.3-3.7GHz), WLAN (5.2-5.9GHz) and Satellite NATO H band (6-8GHz) across the UWB spectrum. Gain is increased by making an incision in the ground structure behind the junction of radiating element and the feedline meeting point. The proposed antenna array is designed and simulated using the High Frequency Structure Simulator (HFSS) software package. After fabrication, the impedance (S11, VSWR) and radiation characteristics of the antenna are measured and compared with the simulated results. The antenna achieves a peak gain of 11.1 dB and demonstrates improved band rejection. The proposed antenna array incorporates notching characteristics tailored to the unlicensed bands within the UWB range. UWB transceivers equipped with this antenna have the potential to operate without interference.

Conventional window functions were capable to provide some desired radiation characteristics at the cost of some performance degradation. For instance, the side lobe levels were reduced at the cost of wider beam widths and lower directivities.  In addition, these non-uniformly window functions require relatively high complex feeding networks due to the large dynamic range ratios (DRR) of the amplitude current excitations. Among all the window functions, the rectangular window gives unity DRR and thus it gives the simplest array feeding network. It also gives good radiation characteristics such as narrower beam width and highest directivity. The only undesirable feature of this window is its highest leakage power outside the main beam of the array pattern. This feature is mainly due to the sharp edges at the ends of the amplitude current excitations. In this paper, a new family of the window functions that combines the desired features of the unit-amplitude rectangular window function with some good features of the non-uniform window functions is proposed. The proposed mixed window functions have unit-amplitudes at the flat center section and maintain the conventional taper-amplitudes at both edges of the array excitations. Moreover, the length of the flat center region of the proposed windows is made variable and it can be specified by the designer to provide best performance. Simulation results show that a best compromise between uniform and non-uniform amplitude windows is feasible and it can be obtained by using the proposed method. 

A balun is an essential component in microwave/RF communication used to convert an unbalanced signal to a balanced signal. It’s used in varied applications like multipliers, power dividers, mixers, and RF microwave components. A wideband branchline balun is proposed. It is a multistage branchline balun designed using half wavelength and quarter-wavelength transmission lines and fabricated for WLAN/WiMAX applications operating in the frequency range of 2.4 GHz. The proposed balun is fabricated using FR4 material, and the size of the balun is 58.7 mm x 36.1 mm. Fractional bandwidth of 58% is achieved. The proposed balun is simple in structure, low cost, planar, has a wide bandwidth, and good isolation between the output ports.

This paper details the design, manufacturing, and measurement of a 37.33 mm × 87.2 mm x 1.6 mm high-bandwidth Cantor fractal slotted defective ground surface (DGS) antenna array (1x2) for the microwave C-band (4–8 GHz) and X-band (8-12 GHz). For exciting a patch antenna, a mutually coupled feed (a special type of corporate feed) is utilized. Mutually coupled feed comes into the category of non-contact feed. Non-contact feeding systems can be designed to minimize electromagnetic interference (EMI), particularly in high-frequency applications. It also avoids impedance mismatches and hence increases the bandwidth and gain. In this paper, the fringing effect has been taken into consideration for proper isolation between the feeding network and patch. This study also ensures minimal mutual coupling and interference between patches while maintaining a uniform radiation pattern. Operating bands of 7.05-8.53 GHz and 10.33–11.43 GHz are all compatible with this architecture. The suggested antenna has promising results in both simulation and measurement. For example, it includes a large impedance bandwidth of 1.48 GHz and 1.1 GHz and a reflection coefficient (S11) of -28.93 dB and -19.62 dB at its resonance frequencies of 7.6 GHz and 10.7 GHz, respectively. Additionally, this achieves a high gain of 10.05dBi at 7.6 GHz and 7.73 dBi at 10.7 GHz. While mutually coupled feed( a special type of corporate feed) is a well-investigated concept in literature, its use in antenna arrays is a novel aspect that has not been previously addressed. Furthermore, the application of cantor-inverted cantor fractal geometry on patch antennas has also remained unexplored in existing literature. This research investigates the implementation of mutually coupled feed in antenna arrays, demonstrating its feasibility and potential benefits while minimizing fringing effects through strategic feed placement.

This paper compares and discusses two different types of Wavelength Division Multiplexing (WDM) Passive Optical Network (PON) configuration. First is with Semiconductor Optical Amplifier (SOA-WDMPON) and second is with Erbium Doped Fiber Amplifier (EDFA-WDM-PON). The performance of the system is measured by calculating Bit Error Rate (BER) for various values of bitrate and length of fiber. The novelty of the paper is that the results are obtained for higher bitrate up to 30 Gbps and higher fiber lengths up to 80 Km. Compared to previously published results this paper tries to achieve good BER and Q-factor. WDM-PON with four channels is designed, incorporating SOA and EDFA amplifiers to achieve optimized gain and noise performance. Unlike previous studies, this paper integrates recent innovations, such as quantum dot SOA and tunable EDFA, into a practical design that addresses critical challenges in high-speed optical networks, including scalability, signal integrity, and costeffectiveness. The importance of this paper is reflected in its comprehensive overview of stateof-the-art developments and its applicationoriented approach, offering valuable insights for optimizing optical amplification technologies for modern and future communication networks.