New determination of resonant frequency of circular disc microstrip antenna: application to thick substrate

1988 ◽  
Vol 24 (17) ◽  
pp. 1104 ◽  
Author(s):  
F. Abboud ◽  
J.P. Damiano ◽  
A. Papiernik
2020 ◽  
Vol 11 (1) ◽  
pp. 101
Author(s):  
Carlo Boursier Niutta

A new approach for the nondestructive determination of the elastic properties of composite laminates is presented. The approach represents an improvement of a recently published experimental methodology based on the Impulse Excitation Technique, which allows nondestructively assessing local elastic properties of composite laminates by isolating a region of interest through a proper clamping system. Different measures of the first resonant frequency are obtained by rotating the clamping system with respect to the material orientation. Here, in order to increase the robustness of the inverse problem, which determines the elastic properties from the measured resonant frequencies, information related to the modal shape is retained by considering the effect of an additional concentrated mass on the first resonant frequency. According to the modal shape and the position of the mass, different values of the first resonant frequency are obtained. Here, two positions of the additional mass, i.e., two values of the resonant frequency in addition to the unloaded frequency value, are considered for each material orientation. A Rayleigh–Ritz formulation based on higher order theory is adopted to compute the first resonant frequency of the clamped plate with concentrated mass. The elastic properties are finally determined through an optimization problem that minimizes the discrepancy on the frequency reference values. The proposed approach is validated on several materials taken from the literature. Finally, advantages and possible limitations are discussed.


2018 ◽  
Vol 7 (2.16) ◽  
pp. 11
Author(s):  
Sanjeev Kumar ◽  
Ravi Kumar ◽  
Rajesh Kumar Vishwakarma

A microstrip antenna with a circular disc design and modified ground is proposed in this paper. Circular shapes of different size have been slotted out from the radiating patch for achieving extended ultra wideband (UWB) with GSM/Bluetooth bands with maximum bandwidth of 17.7 GHz (0.88-18.6 GHz). Further, characteristic of dual notch band is achieved, when a combination of T and L-shaped slots are etched into the circular disc and ground plane respectively. Change in length of slots is controlling the notch band characteristics. The proposed antenna has rejection bandwidth of 1.3-2.2 GHz (LTE band), 3.2-3.9 GHz (WiMAX band) and 5.2-6.1 GHz (WLAN band) respectively. It covers the frequency range of 0.88-18.5 GHz with the VSWR of less than 2. Also, an equivalent parallel resonant circuit has been demonstrated for band notched frequencies of the designed antenna. The gain achieved by the proposed antenna is 6.27 dBi. This antenna has been designed, investigated and fabricated for GSM, Bluetooth, UWB, X and Ku band applications. The stable gain including H & E-plane radiation pattern with good directivity and omnidirectional behavior is achieved by the proposed antenna. Measured bandwidths are 0.5 GHz, 0.8 GHz, 1.1 GHz and 11.7 GHz respectively. 


2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
P. Nageswara Rao ◽  
N. V. S. N. Sarma

The effect of indentation angle of Koch fractal boundary applied to a triangular patch on the resonant behavior and bandwidth is presented. It is shown that the resonant frequency can be controlled by changing the indentation angle of the boundary. With the experimental verification, it is established that for an indentation angle of more bandwidth is obtained compared to conventional .


Author(s):  
Srabani Bhattacharyya ◽  
Dia Ghosh ◽  
Goutam Kumar Singh ◽  
Reema Singh ◽  
Aditya Raj ◽  
...  

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