Microwave filter research in Universiti Teknologi Malaysia

This paper describes four microwave filter configurations that have been recently developed over the past five years. These are a direct coupled cavity waveguide filter, an internally- coupled hairpin-line filter, a meander-gap hairpin line filter and a three-element parallel-coupled filter

Experimental Investigation of CPW Fed Fractal Array Antenna

This paper experimentally investigates the performance of a set of simple two element coplanar waveguide (CPW) fed fractal array antennas. The design is based on the single square microstrip patch antenna, operating at 1.57s GHz. This is the frequency of operation of a Global Positioning Satellite system receiving antenna. The basic patch antenna undergoes the first and second iteration process to form the first and second iteration fractal structures. The array elements are equally spaced between their corresponding centres. Through experimental investigations, it was found that the fractal antenna array operates at lower frequency of operations compared to the basic two element square patch antenna. The second iteration fractal array antenna has the lowest operating frequency, indicating a much more compact radiating structure. However, the reflection bandwidth decreases

Fractal patch antenna for GPS application

Fractal patch antenna is proposed to reduce the size with miniaturization technique, not only for the single element structure, but also in an array design. This paper presents the design of fractal patch antenna based on the basic structure of square antenna operate at 1.575 GHz for global positioning system (GPS) application. The fractal design is introduced into the basic structure intended to reduce the frequency of operation. Hence, miniaturization can be achieved. Simulation has been performed on several sets of the design structures using ensemble SV software. The frequency imposed by the fractal structure is lower than the basic structure

Identification and diversity of Fusarium species isolated from tomato fruits

Fruit rot of tomato is a serious disease caused by Fusarium species. Sampling was conducted throughout Selangor, Malaysia and fungal species identification was conducted based on morphological and gene encoding translation elongation factor 1-α (tef1-α) sequence analysis. Five species of Fusarium were discovered namely F. oxysporum (including F. oxysporum f. sp. lycopersici), F. solani, F. equiseti, F. proliferatum and F. verticillioides. Our results provide additional information regarding the diversity of Fusarium species associated with fruit rot disease of tomato

Micromachined Rectangular Coaxial Line to Ridge Waveguide Transition

This paper discusses a new micromachined rectangular coaxial line to ridge waveguide transition operating in the frequency range from 60 to 90 GHz. The micromachining techniques are used to provide accurate device dimensions for millimeter wave distributed circuits. A 50 Ω coaxial line output is coupled to a relatively high impedance ridge waveguide. A balun (balanced to un-balanced) concept is considered in order to transform TEM mode in the coaxial line to TE mode in the waveguide [4]. The design has been simulated using CST Microwave Studio 3D simulator. The structure is constructed by bonding five layers of gold coated photoresist (SU-8) each 200 microns thick. The experimental result shows a good wideband response with return loss below - 19dB between 60 GHz to 90 GHz. The measurements show a 1 dB insertion loss and the S parameter response giving a good agreement with the simulation result

Micromachined Millimeter-wave Butler Matrix with a Patch Antenna Array

This paper presents a micromachined patch antenna array with an integrated 2x2 Butler matrix (BM) beamformer. It was designed at 63 GHz and simulated using CST Microwave Studio 3D simulator. The BM is made using a low loss air filled rectangular coaxial line. The structure is constructed by bonding five layers of gold coated photoresist SU-8, each 200 microns thick. The experimental result shows a good matching achieved with return loss of -13 dB and inter-port isolation of about -22 dB at 63 GHz

Millimeter wave microstrip antenna with CSRR for 5G application

International audienceThis paper describes the comparison between microstrip antenna and microstrip antenna with CSRR for millimeter wave application. The proposed approach utilized 3 different structures which are a single element, 1×8 array, and 4×4 array. CSRR is applied to the design to increase the number of radiating frequencies. The main advantages of the proposed method are the compact size of the antenna, reduced size, and dual band performance from the antennas. From the simulation work, it is discovered that antennas with CSRR structure has dual band performance and reduced size of antenna patch and substrate. © 2021 IEICE

Micromachined H-plane horn antenna manufactured using thick SU-8 photoresist

A micromachined H-plane horn antenna designed at 63GHz is presented. The horn is integrated with an air filled coaxial line to ridge waveguide transition with the ridge waveguide feeding the horn. The antenna is constructed by bonding five layers of gold coated SU-8 photoresist, each 200μm-thick. The performance has been validated experimentally using on-wafer probe measurements. A good match is achieved with low return loss obtained at the designed operating frequency. This proposed design is to be used in three-dimensional phased array beamformers

Dual band dielectric resonator based metamaterial antenna

A dielectric resonator based metamaterial antenna is presented for dual band operations. The hybrid design uses the dielectric resonator (DR) and split ring resonator (SRR) to radiate two resonant modes. The antenna has a compact size of 40 × 40 mm2. The peak realized gain of 6.24 dBi and 6.04 dBi is obtained at 5.5 GHz and 5.8 GHz respectively. Also a peak efficiency of 94% is obtained across the covering frequency. The antenna has potential applications for WiMAX (5.5 GHz) and WLAN (5.8 GHz) operations