Khaled Mahbub Morshed

Numerical analysis of impedance matched Inverted-L antennas for Wi-Fi operations

This paper presents the numerical simulations of Inverted-L and stair inverted-L antennas capable of generating high gain with less than 1.5 dBi gain variation within the −10 dB return loss bandwidth for 5.5 GHz wireless-fidelity (Wi-Fi) operation with and without resistor-inductor-capacitor (RLC) impedance matching network. Moreover, the proposed antennas can provide bandwidth of 510 and 120 MHz respectively, making it easily cover the required bandwidths for Wi-Fi operation in the 5.5 GHz band. In application of matching network, the input impedance of the antennas well matched to the feeding cable, also improvement in return loss and voltage standing wave ratio (VSWR) is achieved.

Numerical and Experimental Analysis of Impedance Matched Inverted-L and Stair Inverted-L Antenna for 5 GHz WLAN Operation

This paper presents impedance matched high gain inverted-L antenna (ILA) and stair ILA for 5 GHz wireless local area network (WLAN) by means of numerical and experimental analysis. Numerical simulation is carried out using method of moments in Numerical Electromagnetic Code (NEC-2) and agilent vector network analyzer, watts antenna trainer, and microwave engineering trainer are used for the measurement. The experimental results show that ILA and stair ILA has 10-dB return loss bandwidth of 650 MHz (5170 - 5820 MHz) and 360 MHz (5320 - 5680 MHz) respectively covering the unlicensed national information infrastructure (U-NII) mid frequency bands for 5 GHz WLAN operation. Omnidirectional radiation patterns are achieved for both antennas in XY plane and the antennas have peak gain of 6.65 and 10.987 dBi respectively at center frequency (5.5 GHz) of antenna operating bandwidth. Moreover, the antennas have radiation efficiency of greater than 84% and 91% respectively within the return loss bandwidth.

Compact dual L-slit slotted antenna for spacecraft, WLAN, Wi-Fi, and Bluetooth application

In this paper a compact dual L-slit slotted microstrip antenna for entire unlicensed national information infrastructure (UNII) band (UNII low 5.15-5.25 GHz, UNII mid 5.25-5.35 GHz, UNII worldwide 5.47-5.725 GHz and UNII upper 5.725-5.825 GHz) is proposed. This compact (15 × 9 mm size) antenna has good characteristics to cover UNII band for 5.2 GHz WLAN, 5.5 GHz Wi-Fi and 5.8 GHz WLAN & Bluetooth operation. In addition it covers 2.7-2.8 GHz frequency band (~95% bandwidth coverage) for spacecraft application. Coaxial feeding is used and analysis has been done using IE3D software. The antenna provides radiation efficiency, gain and VSWR are 93.41%, 6.5 dBi and 1.01 at 5 GHz frequency band and 48.09%, 1.8 dBi and 1.55 at 2.7 GHz frequency band respectively. Aside this the proposed antenna has accomplished the perfect impedance matching 49.41 Ω without any matching network.

A simple structured planar wire antenna for wireless communication applications

A simple structured planar wire antenna for WiMAX, Wi-Fi, WLAN, Bluetooth and satellite communication applications is presented. The antenna has four significant frequency bands with bandwidth of 194 MHz (2.956 - 3.15 GHz), 454 MHz (5.196 - 5.65 GHz), 79 MHz (6.538 - 6.617 GHz), and 424 MHz (12.812 - 13.236 GHz). The antenna is assumed to be feed by a 50 Ω coaxial cable. Application of RC network improves the antenna impedance behavior. It shows unidirectional radiation pattern with sufficient antenna gain. The antenna design cost is very low and about 200 BDT.

Wideband planar monopole antenna for LTE, GSM, Bluetooth, WiMAX, DCS, PCS, and GPS mobile terminals

A simple planar antenna of high gain for long term evolution (LTE), global system for mobile communications (GSM), Bluetooth, worldwide interoperability for microwave access (WiMAX), digital cellular services (DCS), personal communication services (PCS), wireless local area network (WLAN), and global positioning system (GPS) mobile terminals is presented. The antenna has wide -6 dB reflection coefficient bandwidth of 2.17 GHz (1.33 - 3.5 GHz). The antenna has a compact size of 44.9 mm ×35.5 mm × 0.87 mm placed one side of the substrate of dimension 35.5 mm × 75.5 mm. The antenna has high gain of 3.85 dBi at 2.7 GHz, maximum directivity is 5.04 dBi at 2.7 GHz and total efficiency of the antenna varies between 61% and 95% within the wide impedance bandwidth. In addition, the antenna gain and efficiency is almost constant in individual operating band of operation. Dimensions of the antenna are optimized for wide impedance band. Antenna radiation patterns are presented at 1.5, 2, 2.5, and 3 GHz.

A high-gain slot-loaded microstrip patch antenna fed by a half-width microstrip line for 5.5 and 5.8 GHz Wi-Fi/WiMAX applications

A new type of antenna is presented in this paper. The main structure is a slot-loaded microstrip patch antenna fed by a half-width microstrip line. Two different types of antenna structure are combined together to make a single element antenna, and the radiation properties of both antennas are utilized in the proposed highly efficient antenna. Radiation from the antenna structure is achieved primarily from the first higher-order microstrip mode. The 10 dB return loss bandwidth of the antenna is 640 MHz (5.41 GHz to 6.05 GHz). The antenna produces a directive beam with a peak gain of 9.1 dBi, and the variation of the gain within the 640 MHz impedance bandwidth is only 1.35 dB.

Highly Efficient Leaky-Wave Antenna Array for 28-GHz Millimeter-Wave Terminals

A highly efficient leaky-wave antenna (LWA) array is presented in this paper. The proposed LWA array covers 28-GHz millimeter-wave frequency band and can be useful for 5G terminals. The antenna has been designed to be integrated to a substrate of dimensions 120 mm × 70 mm and occupies a small area of 24.5 mm × 24.5 mm. A dielectric load is used to increase the antenna efficiency. The efficiency of the array varies between 97\% and 98\% within the 28-GHz millimeter-wave band. It has a wide operating bandwidth of 6 GHz (26 - 32 GHz) and a peak gain of 9.1 dBi at 28 GHz. Within the 28-GHz millimeter-wave band the proposed LWA array has stable boresight radiation in the x-z and y-z planes.

A compact, wide-beam, high gain antenna for wearable medical body-area network devices

A compact and low-profile wearable antenna for wireless body area network devices operating at 5.8 GHz ISM band is presented. The dimensions of the antenna are 9.5 mm × 16 mm with a wide impedance bandwidth of 650 MHz (5.42-6.07 GHz). Dimensions of the antenna are optimized using CST Microwave Studio. The antenna has a high directive gain of 6.9 dBi with less than 0.15 dB gain variation, having radiation in broadside, i.e. towards out of the body. Maximum allowed power to the antenna is 2.21 mW and 26.11 mW at 1-g and 10-g, respectively. Input power limited by the average SAR to the antenna are almost constant within the operating bandwidth. The antenna has wide radiation beamwidth, half power beamwidth, of 114.10 and 91.60 with a very low side lobe level of -9.7 dB and -12.5 dB in YZ and XZ plane, respectively.

Weighted momentum based motion detection methodology for handoff in wireless networks

This paper presents efficient motion detection of mobile node (MN) based on weighted momentum of received signal strength (WMRSS) in support of better handoff management in wireless network. In this method, for making momentum of received signal strength (MRSS) more accurate in detecting motion of MN, weight is applied to the received signal strength (RSS) of MN according to the priority and weighted average determined in calculating exponential moving average (EMA). To make WMRSS more effective and sensitive to the motion of user, dynamic smooth factor is used hence the method is called dynamic WMRSS (DWMRSS). Numerical simulation results are presented for DWMRSS method and compared with DMRSS scheme. Obtained result shows that the proposed method detects the motion of MNs more effectively and helps to reduce unnecessary handoff and loss of power.

A compact loop type antenna for millimeter band applications

A millimeter band microstrip patch antenna was developed to achieve a bandwidth of 2GHz from 58.995GHz to 60.995GHz with linear polarization capability. In this paper the key configuration of the antenna consists of two loops having an opening at opposite side. The bandwidth of the antenna is enhanced by taking the advantage of this double loop arrangement and the mutual coupling between the inner and outer loops. In this paper, properties of the proposed two loop antenna are investigated in the frequency range from 58.995 GHz to 60.995 GHz which is efficient for satellite millimeter band applications.