Rajesh Saha

Enhancementof gain, bandwidth and directivity of a patch antenna by increasing dielectric layers of the substrate through micromachining technique for RFID application

Bandwidth is the primary resource of any communication system, as the radio spectrum is fixed. The high gain and directivity is also the major issue for a wireless network. Microstrip antenna has popular attractive features such as low profile, low cost, small size and easily integrated with RF devices; but has narrow bandwidth and low gain. This paper comprises one novel technique in order to increase the bandwidth, gain and directivity of the conventional rectangular patch antenna. In this paper gain, directivity and bandwidth of a conventional patch antenna is enhanced by increasing dielectric layer between the patch and ground through silicon micromachining technique. In Radio Frequency Identification (RFID) technology, these types of antenna provide superior performance and all the simulation has been carried out in high frequency structure simulator (HFSS).

RF MEMS and CSRRs-based tunable filter designed for Ku and K bands application

Abstract This paper presents the design and simulation of a reconfigurable stop-band filter on a silicon substrate based on the combination of RF microelectromechanical system and metamaterial-based technologies. The device is implemented on coplanar waveguide structure by embedding complementary split-ring resonators on the central line and an RF MEMS varactor bridge supporting the neighboring ground planes. The response characteristics of this metamaterial-based filter can be dynamically tuned, thus enhancing its usefulness. The device operates within a frequency range of 16.5–19.5 GHz, giving a tuning range of 15%, and can be tuned from Ku-frequency band to K-frequency band. It works with a comparative low pull-in voltage of 17.42 V and a faster switching time of 0.138 µs. A thorough electromechanical analysis has been done by varying various structural and material parameters. Moreover, a comparative electrical performance of silicon and glass has been shown to overcome the cons of silicon by high-resistivity glass.

Dual band operation using metamaterial structure for Radio Frequency Identification (RFID) system

The important functions of Radio Frequency Identification (RFID) technology are radiation and detection. So efficient antenna design and fabrication is the unique solution which perform a very crucial role for many applications. The reader and tag intense are component of the RFID system. In this paper designed has done on RFID antenna for tag and reader application, which also includes the different types of antenna (UHF application, wideband, multiband antenna) and the general consideration for design, them which are currently used for tag and reader application. In this paper we proposed a rectangular patch antenna and then designed a metamaterial structure on the patch to improve the antenna performance.

Multiple Inputs Combinational Logic Minimization by Minterms Set

The paper presents an easy technique to simplify multiple inputs combinational digital logic circuits. By grouping of minterms in different sets, multiple inputs can be easily synthesized. The proposed technique is an exact method of minimization. The new approach reduces the minimization complexity of combinational circuits. The proposed method is fast, can be solved by paper–pen, and also by computer programming.

Analysis of Pull-in-Voltage and Figure-of-Merit of Capacitive MEMS Switch

Theoretical and graphical analysis of pull-in-voltage and figure of merit for a fixed-fixed capacitive Micro Electromechanical Systems (MEMS) switch is presented in this paper. MEMS switch consists of a thin electrode called bridge suspended over a central line and both ends of the bridge are fixed at the ground planes of a coplanar waveguide (CPW) structure. A thin layer of dielectric material is deposited between the bridge and centre conductor to avoid stiction and provide low impedance path between the electrodes. When an actuation voltage is applied between the electrodes, the metal bridge acquires pull in effect as it crosses one third of distance between them. In this study, we describe behavior of pull-in voltage and figure of merit (or capacitance ratio) of capacitive MEMS switch for five different dielectric materials. The effects of dielectric thicknesses are also considered to calculate the values of pull-in-voltage and capacitance ratio. This work shows that a reduced pull-in-voltage with increase in capacitance ratio can be achieved by using dielectric material of high dielectric constant above the central line of CPW.

A Novel MEMS-Based Frequency Tunable Rectangular Patch Antenna

This paper comprises of a frequency tunable patch antenna on which a U-shaped metamaterial structure is designed. The antenna is loaded with coplanar waveguide (CPW) stub on which two MEMS shunt switch with capacitive gap of 1.5 \( \upmu{\text{m}} \) were placed at 0.2 mm distant from each other. The tunability in frequency is achieved by changing the gap between the bridge and the insulating layer, at up state of the switches. The antenna resonant frequency shifted from 10.54 GHz down to 10.52 GHz by changing the capacitive height from 1.5 to 1 \( \upmu{\text{m}} \). The simulation of designed model has been carried out in Ansoft HFSS and different antenna parameters like gain, radiation pattern, efficiency, and scattering parameter have been adopted in this paper.

Metamaterial based patch antenna with omega shaped slot for RFID system

Radio Frequency Identification (RFID) is one of the implementations under auto identification (AUID) technique. It is basically used in identification of items, animals, books etc. The patch antenna is a trendy resonant antenna for narrow-band microwave wireless link applications such as RFID systems. In this paper a rectangular micro-strip patch antenna is designed and thoroughly analysed. Taking into consideration different antenna parameters like directivity, bandwidth, and gain etc., an improved version from the simple rectangular patch has been developed by introducing a bi-anisotropic omega shaped metamaterial within the patch, also known as reciprocal metamaterial. The results obtained after simulation in High Frequency Structure Simulator (HFSS) were so much effective with the considerable enhancement in the values of directivity, bandwidth. Modelling of this omega shaped patch antenna has revealed results that are suitable for RFID antenna design.

Low-Cost Crash Protection System for Heavy Motor Vehicles

This paper proposes the use of an ultrasonic sensor module which is used to calculate the ground clearance of a heavy motor vehicle (HMV). The sensor calculates distance based on the estimation of the travelling time of an ultrasonic pulse, transmitted by an ultrasonic sensor, which gets reflected back from the ground. These low-cost sensors seem ideal to be housed underneath HMVs running in hilly areas with narrow roads, which have the risk of falling off the cliffs in sharp turns. The sensors will be placed such that whenever the vehicle’s rear wheel senses a height more than that of the wheel by a considerable amount, the vehicle will move away from the cliff and the automatic braking system will be activated. The system may be used similarly in dumper HMVs that need to fill large shallow holes with mud, sand, etc.; the sensor will be placed differently in such condition.