Design of multi-port network utilizing microstrip-slot technique for ultra wideband system

Nowadays, there is a lot of interest on the research and development related to ultrawideband system due to the increasing demands on the applications with low power, low cost and low interference. Thus, to cope with these demands, various researches are required for the development of front-end microwave components, which include six-port network as an alternative to a mixer-based design. The configuration of a six-port network is constructed by combining coupler and power divider. In the interest to have a simple design and convenient usage to form the sixport network with ultra wideband (UWB) operation, new power divider and coupler are designed by using microstrip-slot technique. All the proposed designs are simulated via the use of CST Microwave Studio 2010 and realized using Rogers TMM4 with a conductor coating of 35 μm, thickness of 0.508 mm and dielectric constant of 4.5. The developed prototypes of the proposed designs are verified by measurement using a vector network analyser (VNA). In this thesis, a design of twosection power divideris proposed with a great UWB performance of -3.8 dB ± 0.5 dB transmission coefficient and 0º ± 2º phase difference. This power divider has bandwidth improvement of 11.9% and size reduction of 23.33% compared to the conventional design. Meanwhile, for the coupler design, a UWB coupled-line coupler with zig-zag-shaped slot that has 3 dB ± 2 dB coupling coefficient and -90º ± 5º phase difference is proposed. The proposed coupler has 109.5% bandwidth improvement with the length reduction of 20% compared to the conventional coupler. The proposed UWB coupler is then implemented into a new proposed structure of UWB 90º power divider. Then, three configurations of six-port networks formed by UWB coupler, two-section power divider and 90º power divider are designed; which are named as Type I, Type II and Type III. From the observation, Type III demonstrates the best UWB performance with magnitude imbalance of ± 5 dB and phase imbalance of ± 10° that achieving the specified UWB design goal. Furthermore, Type III has the respective size reduction of 57.16% and 34.67% compared to Type I and II. In addition, by comparing to the previous works, the proposed design has broadest bandwidth of 100% and smallest size of 50.92 mm x 35 mm. Hence, the proposed six-port network has very well UWB performance with relatively compact size and simple design, which is easy to be fabricated

Analysis on the effect of dielectric material and copper thickness of substrate towards the performance of ultra wideband ground slotted T-shaped power divider

Nowadays, the fifth generation (5G) wireless system is extensively studied to fulfill the continuously increasing demand for high data rate and mobility in wireless communication applications. Thus, to cope with this demand, various researches are required for front-end microwave components, which includes power divider. Therefore, in this article, the design and analysis of ultra wideband T-shaped power divider is presented. Two substrates are chosen in the design, which are Rogers RO4003C and TMM4 with copper thickness of 17 µm and 35 µm to analyze their effect towards ultra wideband performance of the designed power divider. The design and analysis are performed by using CST Microwave Studio. The optimal performance of the designed power divider is subjected to dielectric material and the copper thickness of the substrate. Where, the best design is obtained using TMM4 substrate that made of ceramic thermoset polymer with 35 µm copper thickness

Development of an Airflow Monitoring System for Air Handling Unit using IoT

This paper presents the development of an airflow monitoring system for air handling units using NodeMCU ESP32. The main purpose of this project is to improvise the use of microcontroller with on-par performance for industrial applications. This proposed system consists of two sensors that measure airflow from the air handling unit. The first sensor is an airflow speed, which measures the airflow speed from the air handling unit. The second sensor detects and indicates the temperature and humidity of the airflow. The testing parameters show very good correlations among variables, indicating the efficiency of the system to monitor the airflow. Keywords: Airflow, IoT, Temperature, Humidity, Air Handling Unit eISSN: 2398-4287 © 2022. The Authors. Published for AMER ABRA cE-Bs by E-International Publishing House, Ltd., UK. This is an open-access article under the CC  BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under the responsibility of AMER (Association of Malaysian Environment-Behavior Researchers), ABRA (Association of Behavioral Researchers on Asians), and cE-Bs (Centre for Environment-Behavior Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia

Heart rate sensor with IoT features

This paper describes the working of a heartbeat sensor project aimed at creating an internet-enabled heart rate monitoring device, combining the ESP32 microcontroller, MAX30102 pulse oximeter sensor, and OLED display. The device transmits real-time data to a webpage, allowing users to monitor their heart rate conveniently. Challenges included securing a stable internet connection and optimizing power consumption. Potential applications range from remote patient monitoring to fitness tracking, promoting healthier lifestyles. The project demonstrated the convergence of IoT and health monitoring technologies. Plans involve refining the device’s capabilities and enhancing user experience

Design of U-shaped in-phase power divider employing ground-slotted technique for wideband applications

This article describes the design of U-shaped wideband power divider implemented with ground-slotted technique. The slotlines at ground plane underneath second and third arm promises wider bandwidth performance. In this proposed designed, the second and third arms are formed by microstrip line with J-shaped slot underneath. In order to obtain the impedance and dimension of microstrip line and slot forming the quarter-wave transformer, the new equation is proposed and discussed in this paper. The relation between characteristic impedance of microstrip-slot transmission line (Zm-s) with slot width (Ws) and microstrip impedance (Zm) is obtained by using completing square curve fitting method. To realize the circuit, substrate Rogers TMM4 is used. The thickness of the substrates is 0.508 mm with dielectric constant of 4.5 and 35 μ m cooper coating. The performance of power divider is formulated by using commercially available CST Microwave Studio. The performance of the fabricated device is then compared with simulation. The optimum result has been achieved over wideband frequency with the measured and simulated result show reasonably comparable performance between 4 and 11 GHz

A Review of Malaysia’s Aerospace Manufacturing Post-COVID19 Pandemic Using Michael Porter’s Five Competitive Forces Model

Developing a team of business risk assessors in pursuit of establishing an aero-manufacturing company is necessary in producing desired outcomes. Quantitative assessment had proven to be reliable and accurate, however this comes with a cost. Therefore, this paper attempts to discuss the elements of risks and threats involved in establishing an aero-manufacturing business post COVID-19 pandemic, in a qualitative manner. It acts as a preliminary report, and a qualitative review of existing literatures related to the airlines and aerospace industry. The risks and threats data and justifications are then categorized and compiled according to Michael Porter’s Five Competitive Forces Model (FCFM) in an attempt to visually map the threats and risks involved with the business, either directly or indirectly. Based on the discussion, the overall impact is structured into a comprehensive table which will give interested parties an overall view of the assessment

IOT gas leakage detection, alert, and gas concentration reduction system

LPG is a common industrial and household item, which is extremely flammable. Many accidents have occurred because of LPG leaking, whose causes range from improper installation to the usage of faulty gas cylinders. Serious accidents that cause bodily harms or even fatalities can be avoided if the leakage is detected early before it initiates huge fires and causes damage to the surrounding where the LPG container is installed. This study proposes and develops an improved design of a system which detects LPG leakage, such as methane, butane, or any other petroleum-based gaseous liquid. Combining the gas leakage detection system with an IoT system shall provide mechanism to instantly contain the severity of LPG leakage and send instant alerts. In this system, an MQ-6 sensor and NodeMCU with ESP8266 WIFI module are used to detect gas presence, in which a relay will turn on to activate an exhaust fan to instantly reduce gas concentration whilst sending alert notification to user via an app. The information will then be transmitted over the internet to a database, in which the information will be accessible via an app configured specifically for the accessibility by the user

Design of ultra wideband 3 dB coupled-line coupler and 90° power divider with zig-zag-shaped slot for wireless communication applications

This paper proposes the new design of compact ultra wideband (UWB) 3 dB coupled-line coupler and 90° power divider. The proposed coupler utilizes zig-zag-shaped slot at the ground plane underneath microstrip coupled-line to enhance the bandwidth and coupling strength significantly. The technique has alleviated the need of a very narrow spacing between parallel coupled-line for easier fabrication process. The proposed coupler is then being implemented into the new proposed structure of 90° power divider that requires an appropriate phase difference of −90° with equal power division across UWB frequency range. The design of 3 dB coupled-line coupler and 90° power divider are realized using Rogers TMM4 substrate, which simulated by using CST Microwave Studio. Excellent UWB performances are achieved in terms of input reflection coefficient, isolation, coupling factor and transmission coefficients

The design of ultra wideband six-port network by using ground-slotted technique

A new design of compact ultra wideband (UWB) six-port network by using ground-slotted technique is presented in this paper. The proposed six-port network is accomplished by constructing four in-phase two-section power dividers and two 90o power dividers by using CST Microwave Studio 2010. The presented result shows that the proposed UWB six-port network offers good amplitude and phase characteristic performances for frequency range of 3.1 to 10.6 GHz. © 2014 Warsaw University of Technology (WUT)