In this article, the ultra‐wideband tapered patch antenna with fractal slots for dual notch application is presented. The antenna is printed on FR‐4 low‐cost substrate with relative permittivity of 4.4 and thickness of 1.6 mm. Total dimensions of the antenna is 45 × 44 × 1.6 mm3. In here, fractal slots was applied to represent dual notch band characteristics. The final antenna as demonstrated in this article has two rejection bands at 3 and 5 GHz and the antenna covers 2.1–12 GHz frequency band with the VSWR of less than 2. The current distribution in notch frequency and efficiency was checked for the whole frequency band and the maximum antenna gain is between 2 and 6 dBi. Finally, the experimental results are compared with the HFSS simulation ones. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1344–1348, 2014

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This paper presents the design of the Archimedean Spiral Antennas (ASA) backed by a metal plate. The dimension of the spiral arm was designed to operate between 3.1-10.6 GHz and different permittivity of the dielectric substrate was employed between the spiral arm and the backing plate with specified electrical thickness of λ g /4 at the lowest frequency range. The CST simulated results shows that when the dielectric permittivity, ε r increases, the performance of the ASA in terms of return loss, axial ratio, efficiency, pattern and gain deteriorates.

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This paper presents the parametric study effects on the performance of two arm Archimedean spiral antenna. The effects of arm width were investigated in order to obtain an improved return loss, high gain, good axial ratio, high radiation efficiency and good radiation pattern throughout the frequency band of 3.1-10.6 GHz. The investigation of the parametric effects was done through simulation in CST software. Unidirectional radiation pattern is achieved when the spiral antenna is placed over a conducting ground plane. The results revealed that antenna’s performance is directly proportional with the increment of the arm width. Also the study finds out that arm width mainly affects the gain and axial ratio compared to the other antenna characteristics while arm spacing affects the return loss and gain of the antenna, as the arm spacing is increased the return loss and the gain of the antenna improved.

This paper provides background information about the underpinning theory of the model of job demands-resources model (JD-R model), which is the conservation of resources theory. The Conservation of resources (COR) theory became highly popular among researchers. Conservation of resources (COR) theory postulates the link between job demands-resources, personal resources, organizational commitment, work engagement, turnover intentions, and job performance. This paper discusses COR theory, which is the main theory that underpins the present research. This paper reviews the assumptions and development of the theory and presents an overview of important findings obtained with the theory and its association with JD-R model. The paper concludes with an agenda for future research and a brief discussion of the practical application of the theory in JD-R model.