5.75 GHz Microstrip Bandpass Filter for ISM Band

This paper presents on 5.75 GHz bandpass filter based on IEEE802.11a standard for wireless LAN application. The development of bandpass filter includes calculation, simulation, testing and measurement of the filter parameters process has been presented. Simulation software for this project used Ansoft Designer software. The filter operates at center frequency of 5.75 GHz with 100 MHz bandwidth and insertion loss below 10 dB. The bandpass filter contributes to the application of direct conversion front-end receiver for WLAN application at 5.8 GHz frequency

SINGLE STAGE RF AMPLIFIER AT 5.8GHZ ISM BAND WITH IEEE 802.11a STANDARD

This paper describes the circuit design and measurement of a single stage RF amplifier for 5.8 GHz-band with IEEE 802.11a standards for WLAN applications.The circuit was simulated using Ansoft Designer where a 14dB of gain; input and output return loss less than -10dB were observed. The GaAs Hetrojunction FET (HFET), capacitors and resistors are combined with the microstrip line pattern by silver epoxy. A 1dB output power compression point (P1dB) of 17dBm and 14.56dB of gain when -1dBm power injected under 6V and ½ Idss biasing are measured

Transparent Butler Matrix using Micro-metal Mesh conductive film as a conducting element

This paper present the design and performance results of transparent Butler Matrix (BM) using Micro-metal Mesh (MM) conductive film as a conducting element and a glass as a substrate. The transparent Micro-metal Mesh (MM) conductive film have a very remarkable properties. Not only high optical transparency, it also high in electrical conductivity. It has a sheet resistance of 0.7 Ω/sq and a visible-light transmission (VBLT) of 75% respectively. The transparent Butler Matrix (BM) operates at 2.45 GHz frequency. These type of Butler Matrix (BM) can be installed to the glass surface of the building for the future 5G wireless communication internally where beam forming is required

Flexible branch-line coupler using rubber conductive Zoflex for conformal application

This letter presents the design of a flexible branch-line coupler (BLC) using a rubber conductor (Zoflex) as the conductive element and polydimethylsiloxane (PDMS) as a substrate. The BLC is meant to operate at 6 GHz operating frequency. The use of PDMS material as a substrate for the BLC design adds a special characteristic of the PDMS on this passive microwave device. The PDMS has some unique properties such as transparency, durability, and lightweight. Moreover, its high electrical resistivity of 2.9 × 1014 Ω m and moderate dielectric constant of 2.7 make the PDMS a good substrate material for flexible devices. This desirable property gives the proposed device full range of flexibility and a great advantage in terms of durability without degrading the performance of the BLC. From the results obtained for bending and non-bending conditions, it can be seen that within the frequency range of operation, both the return loss and the isolation are kept below the theoretical value of −10 dB. The slight difference observed in the simulated and measured FBWs is due the fabrication tolerances

Bandwidth enhancement on branch line coupler using magneto-dielectric polymer substrate (PDMS-Fe304)

In this paper, a comparative study has been conducted to analyze the bandwidth enhancement on Branch Line Coupler when using magneto-dielectric polymer substrate (PDMS-Fe304) also known as (Polydimethylsiloxane-Iron Oxide). A branch line coupler based on magneto-dielectric polymer substrate was designed and simulated to evaluate the contribution of such promising material in microwave component performance. The purposed branch line coupler was design and simulate to ensure branch line coupler that used magneto-dielectric polymer substrate can achieved higher bandwidth enhancement. All of the branch line coupler will operated on 2.45 GHz operating frequency. The result for (S11) parameter on purposed branch line coupler using magneto-dielectric polymer substrate was show an astonishing enhancement in bandwidth up to 1260 MHz compare to 950 MHz and 720 MHz for Rogers and FR-4 substrate. The phase difference on the magneto-dielectric polymer substrate (PDMS-Fe304) show a significant improvement bandwidth at 2 to 2.7 GHz with 90° ± 5°, better than normal conventional substrate branch line coupler

Case study on prototyping educational applications using persona-based approach

In the twenty-first century, many technologies and applications have been developed to support the digital learning environment for teachers and students either physically in class or virtually at home. The need has increased due to the current COVID-19 pandemic, as students must join online teaching and learning at home either they are at primary, secondary, or tertiary levels. Since the requirements are different according to the level of education, some educational applications are not suitable and complicated for lower education levels. Considering various users' needs, persona-based approach has been used in many studies to elicit users' requirements and derive diverse scenarios from user personas before moving to implementation stage. Thus, this case study proposes a persona-based approach to identify students' goals or needs, pains or challenges besides their satisfaction when using educational application prototypes. It involved eight prototypes for learning Computer Science topics and 29 secondary school students. The findings conclude how the persona-based approach can be used to investigate diverse users' needs, challenges, and scenarios as the inputs to design educational applications with digital contents or e-contents for specific topics or subjects

Flexible microstrip grid array polymer-conductive rubber antenna for 5G mobile communication applications

A flexible microstrip grid array antenna (MGAA) fabricated by printing the patch and the ground plane using a 0.25-mm-thick conductive rubber layer onto a 1.9 mm thick Polydimethylsiloxane (PDMS) substrate layer is presented in this article. The proposed antenna was designed to operate at 14 GHz frequency band. It is composed of 24 radiating elements to achieve a high gain and compact size characteristics. The measurement results shows that the antenna exhibits wideband characteristics in return loss (S11) covered from 12 to 18 GHz and it can works at bending state without sacrificing the performance. The measured radiation pattern results also present good agreement with the simulated results. All the criteria of this proposed antenna make it as a suitable candidate to be applied for future flexible and conformal-5G mobile communication applications

Use and management of Nipa palm (Nypa fruticans, arecaceae): a review

10.1007/BF02858921Economic Botany422206-213ECBO