Madhur Deo Upadhayay

Bio: Madhur Deo Upadhayay is an academic researcher from Shiv Nadar University. The author has contributed to research in topics: Antenna (radio) & Patch antenna. The author has an hindex of 5, co-authored 54 publications receiving 97 citations. Previous affiliations of Madhur Deo Upadhayay include Indian Institute of Technology Delhi & Indian Institutes of Technology.

Optimization Analysis of a Nano-dot Photoconductive Antenna

Abstract: The Photoconductive Antenna (PCA) is a compact and simple source for terahertz radiation. It is based on optical-to-electrical conversion principle to generate terahertz radiation. The major challenge with a PCA is its very small efficiency. The efficiency of a PCA majorly depends on the current pulse amplitude generated across the electrodes gap. Its amplitude can be increased by utilizing various methods, one of them is the use of nano-dots at the electrodes gap. The proposed study analyzes the effect of the shape and size of the nano-dots on the PCA current pulse amplitude. For the analysis, cuboid and cylindrical shaped nano-dots with varying separation between the dots have been taken. The results show that using an optimized combination of the nano-dots dimensions, shape and, separation distance between them, the current pulse amplitude can be enhanced by 31.3%.

Investigation of Breast Cancer Detection Based on Tissue Sensing Adaptive Radar (TSAR)

Abstract: This work present an analysis of breast cancer is the commonest cancer in urban and rural areas in India and accounts for about 20% to 25% of all cancers in women. And also investigation of breast cancer detection is based on differences in electrical properties between healthy and malignant tissues. Tissue sensing adaptive radar (TSAR) has been proposed as a method of microwave breast imaging for early tumor detection. TSAR senses all tissues in the volume of interest and adapts accordingly. In this paper, the second generation experimental system for TSAR is presented. Materials with electrical properties similar to those in the breast are used for the breast model. A resistively loaded Wu–King monopole antenna is fabricated, and reflections from the breast model over the frequency range of 1–10 GHz are recorded.

Graphene antenna on polyamide for 2.4GHz WLAN applications

Abstract: This paper deals with the design, simulation and fabrication of two graphene antennas. CPW fed rectangular patch antenna with U-shaped slot and inverted U-shaped slot are named as design-1 and design-2 respectively. The resonance frequency of both antennas is 2.4GHz (sub 6GHz range). The antennas are designed to work within the range available for Wi-Fi use. Polyamide kapton tape of thickness 100µm and relative permittivity of 3.5 is used as a substrate. Graphene is used to make the conducting patch, feed, and grounds of the antenna design. Two antenna designs are compared based on different antenna parameters and the best of the two is studied extensively throughout the paper.

Triangular Metamaterial Loaded Antenna for Low RCS Stealth Application

Abstract: This work proposes a design of triangular metamaterial loaded antenna with low RCS, which can be employed for space research and stealth applications. Circular and upturned C-shaped resonating slots are introduced in the rectangular patch to aid in miniaturization and impedance matching respectively. The reduced RCS, triangular SRR and CSRR are entrenched on the top and ground plane respectively; these have the added advantage of a compact unit cell. The two radiating edges of the antenna are loaded with dual-section stepped impedance resonators to curb the reflection of the impinging signal. The proposed antenna resonates at 2.25 GHz with a reflection coefficient of −20.83dB. The gain of the antenna is 4.11dBi, which is typical of a low RCS radiator. The impedance bandwidth is 46.5MHz and the antenna has a low monostatic RCS of −23.796dBsm at the fundamental resonant frequency. Since the antenna has a low RCS at the resonance frequency, it can be utilized for defense and stealth applications.

RF bulk acoustic wave filters for communications

Abstract: Background and History. Resonator and Filter Topologies. Baw Device Basics. Design and Fabrication of BAW Devices. FBAR Resonators and Filters. Comparison with SAW Devices. Films Deposition for BAW Devices. Characterization of BAW Devices. Monolithic Integration. System-in-Package (SiP) Integration. Index.

Holographic generation and orbital angular momentum of high-order Mathieu beams : Special issue on atoms and angular momentum of light

Abstract: We report the first experimental generation of high-order Mathieu beams and confirm their propagation invariance over a limited range. In our experiment we use a computer-generated phase hologram. The peculiar behaviour of the vortices in Mathieu beams gives rise to questions about their orbital-angular-momentum content, which we calculate by performing a decomposition in terms of Bessel beams.

Mode Modulation for Wireless Communications With a Twist

Abstract: Recently, orbital angular momentum (OAM) based vorticose communication has attracted much attention because of its potential to significantly increase the spectrum efficiency (SE) of wireless communications. However, the multiple radio frequency (RF) chains used for multiple OAM modes lead to an unexpected cost for wireless vorticose communications. In this paper, we first propose the mode modulation (MM) based OAM system to allow multiple OAM modes sharing a common RF chain. The proposed MM cannot only reduce the hardware cost, but also boost the SE by introducing the mode as an additional dimension for data transmission. Moreover, without the channel state information (CSI) feedback, we develop an equal-probability mode modulation (EMM) scheme to maximize the SE of MM-based OAM systems with the limited RF chains. In addition, with the CSI feedback, we develop a Huffman coding based adaptive mode modulation (AMM) scheme, which can adaptively choose the OAM modes to further increase the SEs of OAM-based wireless communications. We also develop the joint power and probability allocation policy for the AMM scheme to achieve the maximum SEs for OAM-based vorticose communications. Numerical results demonstrate that the MM can offer a new mode dimension for vorticose communications and the AMM scheme can achieve larger SE than the EMM scheme.

Ultrathin Complementary Metasurface for Orbital Angular Momentum Generation at Microwave Frequencies

Abstract: Electromagnetic (EM) waves with helical wavefront carry orbital angular momentum (OAM), which is associated with the azimuthal phase of the complex electric field. OAM is a new degree of freedom in EM waves and is promising for channel multiplexing in communication system. Although the OAM-carrying EM wave attracts more and more attention, the method of OAM generation at microwave frequencies still faces challenges, such as efficiency and simulation time. In this work, by using the circuit theory and equivalence principle, we build two simplified models, one for a single scatter and one for the whole metasurface to predict their EM responses. Both of the models significantly simplify the design procedure and reduce the simulation time. In this paper, we propose an ultrathin complementary metasurface that converts a left-handed (right-handed) circularly polarized plane wave without OAM to a right-handed (left-handed) circularly polarized wave with OAM of arbitrary orders and a high transmission efficiency can be achieved.