Stacked microstrip patch antenna for high gain application

A novel design technique for enhancing gain that improves the performance of a conventional microstrip patch antenna is proposed. This research addresses a novel wideband probe fed inverted stacked multiple slotted microstrip patch antenna. The design adopts contemporary techniques; probe feeding, inverted patch structure and stacked multiple slotted patch. The composite effect of integrating these techniques and by introducing the novel multiple shaped patch, offer a low profile, broadband, high gain and compact antenna element. The result showed satisfactory performance with maximum achievable gain of about 11.42 dBi. The design is suitable for array applications especially for base station

Reflectarray Antenna with Radar Cross-Section Reduction

This paper presents the design of a low RCS reflectarray at 8.52 GHz by replacing the solid metal sheet behind the antenna with a band stop frequency selective surface. A 50 element linear array of omni-directional elements was used to simulate the far field pattern of a reflectarray with f/D=0.325 in the plane of the elements to assess the effect of an imperfect aperture distribution on the gain and sidelobe levels. It is found that the reflection loss variation across the aperture does not have a significant effect on the radiation pattern of the antenna, because for the layout that was studied, only a few of resonant loops were predicted to give a significantly different loss than the others in the array. Simulated and measured results show that the ‘in-band’ reflection phase response of the structure with metal ground plane and with a periodic FSS ground plane is very similar, however the periodic ground plane reduces the ‘out of band’ reflectivity by more than 4 dB, thereby decreasing its RCS profile to these signals

Analysis of Mobile Phone Antenna Performance within the Head and Hand Phantoms

This paper proposes the effect of the hand-hold position on the electromagnetic (EM) wave interaction of a candy bar type and clamshell type cellular handset and a human head and hand is investigated. The human hand influences the performance of terminal antennas, and it is the main cause for absorption and  detuning. In spite of its importance in mobile-phone design and validation processes, it is still complicated to take it into account because a lack of knowledge in the area. In this paper, a rigorous investigation methodology is described for the study of candy bar, and clam shell mobile phone CAD model is used to numerically investigate the effect of hand phantom of mobile phone antenna radiation performance. The simulation results show that mobile phone grip styles of the hand phantom material properties, wrist and length, and hand phantom sizes and different positions is the important parameter to antenna performance. The grip style has direct implications in  the definition of phantom head. The preference of the handset with respect to the side of the user’s head depends on the mobile phone form factor and size. The results established high reliability and suitability for providing decision rationale for the design of complex high-end multi-band mobile phones

Verifikasi Desain Antena Berbasis Dipol Berbentuk V untuk Pengamatan Garis 21 Cm

21 cm adalah salah satu garis emisi penting didalam astronomi radio. Garis ini umumnya digunakan untuk mempelajari karakteristik galaksi-galaksi. Artikel ini mempresentasikan sebuah antena dipol berbentuk V untuk sistem telekop radio 21 cm, yang berkorespondensi dengan frekuensi pengamatan 1420MHz. Designnya telah diimplementasikan dan diukur. Hasil pengukuran memperlihatkan kesesuaian dengan simulasi, dengan eror frekuensi puncak sebesar 0,7%. SWR yang diperoleh juga cukup rendah, yaitu sekitar 1,14. Antena yang diajukan pada artikel ini berpotensi untuk digunakan sebagai feed pada antena reflektor atau sebagai elemen penyusun pada sebuah sistem antena array

Design and Realization of a Planar Ultrawideband Antenna with Notch Band at 3.5 GHz

A small antenna with single notch band at 3.5 GHz is designed for ultrawideband (UWB) communication applications. The fabricated antenna comprises a radiating monopole element and a perfectly conducting ground plane with a wide slot. To achieve a notch band at 3.5 GHz, a parasitic element has been inserted in the same plane of the substrate along with the radiating patch. Experimental results shows that, by properly adjusting the position of the parasitic element, the designed antenna can achieve an ultrawide operating band of 3.04 to 11 GHz with a notched band operating at 3.31–3.84 GHz. Moreover, the proposed antenna achieved a good gain except at the notched band and exhibits symmetric radiation patterns throughout the operating band. The prototype of the proposed antenna possesses a very compact size and uses simple structures to attain the stop band characteristic with an aim to lessen the interference between UWB and worldwide interoperability for microwave access (WiMAX) band

Electrocardiogram-based parameters for the prediction of sudden cardiac death: a review

There has recently been a resurgence of interest in electrocardiogram-based (ECG-based) parameters in predicting Sudden Cardiac Death (SCD) risk. Accurate and timely SCD predictions are essential clinical practice for physicians to provide effective prevention and treatment. An ECG is a non-invasive and inexpensive diagnostic test, and has been firmly established as a clinical tool for assessing the risk of cardiac disease. The electrocardiographic signal derived from the ECG recording consists of a distinctive waveform that depicts the electrical activity of the heart, which can be analyzed for the identification of abnormalities in the heart rhythm. The parameter or characteristic found in the ECG signal might be important for predicting the SCD. A number of systematic reports by expert meetings and review articles in indexed journals identified ECG-based parameters as QRS duration, QT interval, Signal Average ECG (SAECG), T-wave alternan (TWA), Heart Rate Variability (HRV), Heart Rate Turbulence (HRT), T-peak to T-end (Tpe), fragmented QRS complexes (fQRS), and Early Repolarization (ER). This article reviews the mechanism and morphology of these parameters, which may potentially have a role to play in a future algorithm designed to identify early signs of SCD. As of now, none of the ECG-based parameters have been found to be sufficiently stable to predict the SCD risk. Nevertheless, the combination of two or more of the parameters listed, as suggested in many studies, may become a useful component for predicting SCD in the future

Risiko Gangguan Seksual di dalam Rumah kepada Remaja: The Risk of Sexual Harassment in House to Teenagers

Sexual harassment is a sexually oriented act committed against another person either verbally, non-verbally, physically, or emotionally. Sexual harassment can occur to female teenagers whether they are inside or outside home. This quantitative study used questionnaires that were analysed using SPSS 2.0. The objective of the study is to explore the extent of domestic sexual harassment risk on female teenagers while they are at home. A total of 84 girls from the age of nine to fifteen in Selangor participated in this study where they have received consent from their parents and guardians to participate in this study. This study found that 7.14% of the participants admitted that they like to wear sexy clothes at home and had watched pornographic videos with close family members such as father, brother, uncle, and grandfather. The findings revealed that they had experienced sexual harassment by their family members if they do not maintain the Islamic manners in addition to being excessively exposed to the unlimited information technology facility. The findings also showed that there are unsafe elements towards female teenagers at home if the family well-being mechanism is not properly and well maintained. The implications of this study suggested a development of a mobile application to identify the initial signs of sexual harassment towards female teenagers. ABSTRAK Gangguan seksual merupakan perlakuan berbaur seks yang dilakukan terhadap individu lain sama ada berbentuk lisan, bukan lisan, fizikal atau emosi. Gangguan seksual boleh berlaku kepada remaja perempuan ketika mereka berada di dalam atau di luar rumah. Metodologi kajian menggunakan kaedah tinjauan yang melibatkan kajian kuantitatif dan dianalisis menggunakan perisian statistik SPSS 2.0. Objektif kajian adalah untuk meneroka sejauh mana risiko gangguan seksual berlaku kepada remaja perempuan sewaktu di dalam rumah.  Seramai 84 orang remaja perempuan yang berusia sembilan hingga 15 tahun di negeri Selangor telah mendapat kebenaran daripada ibu bapa dan penjaga masing-masing untuk menjadi peserta kajian. Kajian mendapati seramai 7.14% remaja perempuan mengakui suka berpakaian seksi di rumah dan pernah menonton video pornografi bersama ahli keluarga terdekat seperti bapa, abang, bapa saudara serta datuk. Dapatan juga menunjukkan mereka mengalami gangguan seksual dalam kalangan ahli keluarga sekiranya mereka tidak menjaga adab-adab Islam disamping banyak terdedah dengan kemudahan teknologi maklumat yang tiada batasan. Dapatan juga menunjukkan wujudnya elemen yang tidak selamat kepada anak-anak remaja perempuan yang berada dalam rumah sekiranya mekanisme kesejahteraan keluarga tidak dipelihara dengan baik dan betul. Implikasi kajian ini mencadangkan pembangunan sebuah aplikasi mudah alih bagi mengenalpasti tanda-tanda awal gangguan seksual yang berlaku kepada remaja perempuan

Microwave Breast Phantom Measurement System with Compact Side Slotted Directional Antenna

In this paper, a new, complete, and comprehensive breast phantom measurement system is presented. A side slotted vivaldi antenna is used for breast phantom measurement. The radiating fins are modified by etching six side slots to enhance the electrical length and produce stronger directive radiation with higher gain. This approach reduces the lower operating frequency and increases the gain and efficiency without compromising the size of the antenna. The overall size of the antenna is 8.8 (L) × 7.5 (W) cm 2 or approximately 0.4λ × 0.5λ at the first resonant frequency of 1.79 GHz. The results show that the antenna has a fractional bandwidth of approximately 127% from 1.54 to 7 GHz for return loss less than 10 dB with a directional radiation pattern. The average gain of the proposed prototype is 8.5 dBi, and the radiation efficiency is approximately 92% on average over the operating bandwidth. The fidelity factor for face to face is 0.98, and that for side by side is 0.4479, which proves the directionality and lower distortion of the signal. The prototype is successfully simulated, fabricated, and analyzed. The radiating fins of the proposed prototype are optimized to achieve the desired properties for breast phantom measurement. The antenna is used as the transceiver in a breast phantom measurement system to detect unwanted tumor cells inside the breast. An automated electromechanical imaging system with the necessary data post processing makes it an easy and suitable tool for microwave imaging to detect breast tumors

Ultra-Wideband (UWB) Antenna Sensor Based Microwave Breast Imaging: A Review

Globally, breast cancer is reported as a primary cause of death in women. More than 1.8 million new breast cancer cases are diagnosed every year. Because of the current limitations on clinical imaging, researchers are motivated to investigate complementary tools and alternatives to available techniques for detecting breast cancer in earlier stages. This article presents a review of concepts and electromagnetic techniques for microwave breast imaging. More specifically, this work reviews ultra-wideband (UWB) antenna sensors and their current applications in medical imaging, leading to breast imaging. We review the use of UWB sensor based microwave energy in various imaging applications for breast tumor related diseases, tumor detection, and breast tumor detection. In microwave imaging, the back-scattered signals radiating by sensors from a human body are analyzed for changes in the electrical properties of tissues. Tumorous cells exhibit higher dielectric constants because of their high water content. The goal of this article is to provide microwave researchers with in-depth information on electromagnetic techniques for microwave imaging sensors and describe recent developments in these techniques