Kaushik Mandal

Abstract: This paper presents a very simple comb-shaped single layer microstrip patch antenna with seven operating bands for wireless systems. Eight symmetrical rectangular strips are connected by a single strip to achieve multiple operating bands. The proposed antenna provides maximum number of resonating bands compared to the antennas of its class. Effects of additional strips and the connecting strip on the antenna characteristics are studied. A prototype of the antenna is fabricated for experimental validation. The measured reflection coefficient (S11) and radiation patterns are in good agreement with their simulated counterpart. Measured result shows that the proposed antenna can operate at seven different frequency bands 1.56–1.64 GHz, 1.76–1.94 GHz, 3.62–3.74 GHz, 4.43– 4.48 GHz, 5.02–5.13 GHz, 5.48–5.62 GHz and 5.92–6.02 GHz. These bands cover some of the most useful bands for wireless systems such as GPS (1570.42–1580.42 MHz), DCS-1800 (1710–1880 MHz), PCS-1900 (1850–1990 MHz), WiMAX and WLAN.

Abstract: The microstrip antennas with symmetrical comb-shaped radiator are considered. The influence of depth of the cuts on main electrical characteristics of four- and eight-comb antennas is researched. The resonance frequency, the bandwidth and reflection coefficient are chosen as characteristics. The graphs of unknown dependencies are constructed for the two basic frequencies.

Abstract: The microstrip antenna with a symmetrical rectangular radiator and four teeth is described. The influence of the base geometric parameters of the antenna on the bandwidth at the base frequency was studied. The following geometric parameters of the antenna are selected: the length and the width of the radiator, the depth of cuts, the thickness of the substrate, the length of the ground plane and the width of the feed line. The regression analysis was carried out and the mathematical model describing the dependence of the bandwidth on the length and the width of the radiator and the depth of the cuts was developed. The rootmean-square error and the relative absolute error of the model were calculated. The graphs of the bandwidth dependences on the geometric parameters are presented. It was established that the decrease of the bandwidth values is associated with an increase of the radiator width and the substrate thickness. It was shown that a slight influence on the bandwidth are made by the changes of the radiator length and the depths of the cuts only in the case when the radiator width is much smaller than its length. The proposed formula describing the relationship of the bandwidth with the geometric parameters of the antenna can be used to design a four-tooth antenna with wide bandwidth.

Abstract: A novel multi frequency printed antenna is presented in this article. This type of antennas is very useful for the wireless world of today. The proposed antenna covers the low frequency biomedical band as well as various mobile wireless bands such as GSM bands, Bluetooth, ZigBee, Wi-Fi, WLAN and LTE bands etc. The antenna has multi resonating point between 0.5 and 5.6 GHz. The antenna is compact and its size is 32 × 40 × 1.6 mm3. Coplanar waveguide (CPW) feed is used to excite this antenna. CPW feed improves the bandwidth of every resonating point between the above said frequency range. A detailed parametric study of the proposed prototype is presented in this paper. The results show that gain is improved from low frequency to high frequency range. The radiation pattern is directional, which is the most important need of biomedical and specific mobile wireless applications, and radiation efficiency is also good. The prototype is designed and simulated using HFSS. Further measured and simulated results are compared and a good impedance match is found between them. Overall this antenna can be used as a module with bunch of wireless applications.

Abstract: A symmetrical microstrip six-tooth-shaped antenna is considered. The influence of the main geometric parameters of the antenna on the base frequency is investigated. The main geometric parameters of the antenna include length and width of the radiator, depth of the rectangular cutouts on its radiator, thickness of the substrate, length of the ground and width of the feedline. Regression analysis is carried out and several mathematical models are constructed. The first model describes a relationship of the base frequency with depth of the rectangular cutouts, the radiator length and width. The second model describes a relationship between the wavelength at the base frequency and the geometry of the radiator. The root-mean-square error and the relative error of these models are calculated. For the base frequency and wavelength, graphs of dependencies on the geometric parameters of the antenna are plotted. We establish that a decrease in values of the base frequency and an increase in the wavelength is associated with an increase in the depth of cutouts and the radiator length. We show that a slight influence on the base frequency is caused by changes in width of the feedline, thickness of the substrate and length of the ground. The proposed formulas, describing relationships of the base frequency as well as the wavelength at this frequency with the geometric parameters of the antenna, can be used to design a six-tooth-shaped antenna in a wide frequency range.

Abstract: A compact (0.15 λ l ×0.15 λ l ×0.01λ l ) triple band antenna for WiMAX/ WLAN application is proposed. Compactness and multiband operation is accomplished by utilizing E-type unit cell Defected Ground Structure (DGS) in conjunction with H-shaped slot. The main advantages of the proposed E-type unit cell DGS structure is that each unit cell independently control a set of bands (i.e. Upper E-type unit cell DGS structure controls 2.56 and 3.64 GHz, while lower E-type unit cell controls the band at 5.8GHz). The antenna shows the resonance at 2.56 (lower WiMAX), 3.64 (middle WiMAX) and 5.8 (WLAN) with fractional bandwidth of about 5.44 % (2.5-2.64 GHz), 5.77% (3.53-3.74 GHz) and 1.5% (5.735.82 GHz). Good pattern and impedance matching is obtained at the targeted frequencies.