Basudev Majumder

Bio: Basudev Majumder is an academic researcher from Indian Institute of Space Science and Technology. The author has contributed to research in topics: Antenna (radio) & Radiation pattern. The author has an hindex of 8, co-authored 29 publications receiving 272 citations. Previous affiliations of Basudev Majumder include Indian Institute of Technology Bombay.

Dual-Band Circularly Polarized Split Ring Resonators Loaded Square Slot Antenna

Abstract: A dual-band circularly polarized (CP) microstrip line fed slot antenna using a set of split ring resonators (SRRs) is proposed in this communication. Outer ring connected SRRs are placed on the back side of the slot to create the CP upper band. Diagonally opposite corners of the slot are truncated, which together with the SRRs give CP response in the lower band. The proposed dual-band CP antenna provides design flexibility to control the resonance frequency and sense of polarization at the dual bands, independently. The proposed antenna is designed to operate at 3.1 and 4.7 GHz, which is fabricated and tested. The experimental results show the −10-dB impedance bandwidths of 400 MHz in both the bands and the 3-dB axial ratio bandwidth of 3.1% (from 3.05 to 3.15 GHz) and 4.2% (from 4.65 to 4.85 GHz) in lower and upper bands, respectively. Finally, a metallic cavity is used with the antenna to achieve a unidirectional radiation pattern with front-to-back ratio of more than 15 dB without affecting the impedance bandwidth and CP performance of the antenna.

Low-RCS and Polarization-Reconfigurable Antenna Using Cross-Slot-Based Metasurface

Abstract: This letter presents a polarization-reconfigurable compact slot antenna with reduced radar cross section (RCS) using an asymmetric cross-shaped metasurface (MS). The proposed MS can reconfigure the polarization of the slot antenna between right-hand circular polarization (RHCP), left-hand circular polarization (LHCP), and linear polarization (LP) by rotating it with respect to the center of the slot antenna. In addition, the MS reduces the RCS of the slot antenna significantly in all polarization states. The cross-slot MS is placed just over the planar slot antenna without any air gap. The simulated monostatic RCS of $- $ 19.5 dBsm is observed at 4.4 GHz for LHCP and RHCP cases and $- $ 17.0 dBsm for LP mode of operation. Antenna performance in terms of its input matching, far-field parameters, monostatic RCS, and axial ratio are measured at its three polarization states, which are in agreement with simulated results.

Compact Broadband Directive Slot Antenna Loaded With Cavities and Single and Double Layers of Metasurfaces

Abstract: In this paper, a compact wideband directive metasurface (MS)-based antenna is proposed. A pair of edge-fed slots, assisted by a fictitious short, is used to excite the MS layer which is made up of a periodic arrangement of rectangular loop-based unit cells along both the $x$ - and $y$ -directions. The proposed MS-based slot antenna is compact and provides good matching over the entire bandwidth with a broadside radiation pattern. A metallic cavity and an artificial magnetic conductor-based cavity are integrated on the MS-based antenna to reduce its backward radiation. Finally, a pair of edge-fed slot antennas combined with two layers of MSs having compact ground plane area of 1.04 $\lambda _{0}^{2}$ ( $\lambda _{0}$ is the operating wavelength in free space) is proposed for the improvement of gain, bandwidth, and forward radiation. The overall antenna has a low profile of 0.05 $\lambda _{0}$ . The proposed configuration shows a 21% measured bandwidth with an average gain of 9.6 dB over its bandwidth. Over its bandwidth, the antenna efficiency is >89%. The design is validated by a full-wave simulation study followed by the experimental verification.

Frequency-Reconfigurable Slot Antenna Enabled by Thin Anisotropic Double Layer Metasurfaces

Abstract: A frequency-reconfigurable slot antenna using metasurface (MS) is proposed. Two identical anisotropic MS layers are loaded on top of a slot to achieve the frequency reconfigurability. The MS layer is composed of a periodic arrangement of I-shaped metallic inclusions placed in both the horizontal and vertical directions. The MS layers are fed by a linearly polarized slot antenna. The operating frequency of the proposed antenna is tuned by physically rotating the two MS layers with respect to the centre of the slot antenna. Rotation of the MS layers changes the effective permittivity and the loading on the slot antenna and hence the operating frequency changes. The proposed antenna has a low profile with the thickness of the antenna including the two MS layers being $0.07\lambda_{0}$ . The simulated and measured results show that using the proposed technique, the operating frequency can be tuned from 2.55 to 3.45 GHz with a fractional tuning range of around 28%. The antenna provides a minimum gain of 5.3 dB with the peak gain being 8.3 dB. The efficiency of the proposed antenna is more than 90% over its tuning range.

Dispersion-Engineered Transmission Line Loaded Slot Antenna for UWB Applications

Abstract: A transmission line (TL) loaded, compact, ultrawideband (UWB) square slot antenna is proposed in this letter. The square slot is a microstrip line fed and loaded with an array of periodically perturbed TLs to achieve a UWB response from 2.1 to 11.5 GHz. The slot is designed to resonate at 2.6 GHz. The TLs are dispersion engineered to resonate at several frequencies so as to provide a wideband response. Loading of the engineered TLs on the square slot produced multiple resonances without affecting the fundamental mode of the slot antenna. The proposed antenna design is analyzed using dispersion relations and equivalent circuits. The proposed antenna is fabricated on an RT/Duroid 5880 substrate with a size of 50 × 50 × 1.52 mm3. The antenna performance metrics, such as impedance bandwidth, gain, and efficiency, are experimentally verified. Good agreement is obtained between simulated and measured results.

A Circularly Polarized High-Gain Antenna With Low RCS Over a Wideband Using Chessboard Polarization Conversion Metasurfaces

Abstract: A new approach for the gain enhancement and wideband radar cross section (RCS) reduction of an antenna based on the chessboard polarization conversion metasurfaces (CPCMs) is proposed. Compared with the previous low-RCS antennas, high gain and wideband low RCS of a circularly polarized (CP) antenna are achieved simultaneously. The proposed CPCM is the chessboard configuration of the polarization conversion metasurfaces (PCMs), which is made up of adjoining two-layer substrates with three metallic patterns. Low RCS is realized by 180° (±30°) reflection phase variations between two neighboring PCMs. Gain enhancement is achieved by employing a Fabry-Perot cavity, which is constructed by the PCM and the ground of the antenna. The antenna with CPCM operating at the $X$ -band, excited by a sequentially rotated feeding network, is fabricated and measured. Simulated and measured results show that the left-hand CP gain of the antenna with CPCM is at least 3 dB higher than that of the reference antenna from 8.5 to 9.5 GHz and the monostatic RCS is effectively reduced from 6 to 14 GHz.

Multi-Polarization Reconfigurable Antenna for Wireless Biomedical System

Abstract: This paper presents a multi-polarization reconfigurable antenna with four dipole radiators for biomedical applications in body-centric wireless communication system (BWCS). The proposed multi-dipole antenna with switchable 0°, +45°, 90° and −45° linear polarizations is able to overcome the polarization mismatching and multi-path distortion in complex wireless channels as in BWCS. To realize this reconfigurable feature for the first time among all the reported antenna designs, we assembled four dipoles together with 45° rotated sequential arrangements. These dipoles are excited by the same feeding source provided by a ground tapered Balun. A metallic reflector is placed below the dipoles to generate a broadside radiation. By introducing eight PIN diodes as RF switches between the excitation source and the four dipoles, we can control a specific dipole to operate. As the results, 0°, +45°, 90° and −45° linear polarizations can be switched correspondingly to different operating dipoles. Experimental results agree with the simulation and show that the proposed antenna well works in all polarization modes with desirable electrical characteristics. The antenna has a wide impedance bandwidth of 34% from 2.2 to 3.1 GHz (for the reflection coefficient ${\leq}$ −10 dB) and exhibits a stable cardioid-shaped radiation pattern across the operating bandwidth with a peak gain of 5.2 dBi. To validate the effectiveness of the multi-dipole antenna for biomedical applications, we also designed a meandered PIFA as the implantable antenna. Finally, the communication link measurement shows that our proposed antenna is able to minimize the polarization mismatching and maintains the optimal communication link thanks to its polarization reconfigurability.

A Wearable PIFA With an All-Textile Metasurface for 5 GHz WBAN Applications

Abstract: In this letter, a wearable all-textile metasurface antenna (MSA) for 5 GHz wireless body area network (WBAN) applications is proposed. All the components of the proposed MSA are made of the comfort textile materials. A metasurface with high permittivity values is placed right above a wide-bandwidth planar inverted-F antenna to realize size miniaturization and gain enhancement. The proposed MSA has a profile of 4 mm (0.07 λ 0) and occupies an area of 42 mm × 28 mm (0.77 λ 0 × 0.51 λ 0). Moreover, this antenna realizes a measured peak gain of 6.70 dBi, an average efficiency of 77%, and an operating band from 4.96 to 5.90 GHz that covers the 5 GHz WBAN band. In addition, the on-body studies show that the MSA is suitable for wearable applications.

Metantenna: When Metasurface Meets Antenna Again

Abstract: Metasurfaces, composed of 2-D planar arrays of sub-wavelength metallic or dielectric scatterers, have provided unprecedented freedoms in manipulating electromagnetic (EM) waves upon interfaces. The development of metasurface has always been closely related to antennas. On the one hand, metasurface was developed from reflect arrays/transmit arrays that are used as reflectors/lens of antennas, and most fundamental theories of metasurfaces are directly borrowed from antenna array theories; on the other hand, the development of antennas was flourished and expedited by progresses in metasurfaces. Many emerging antenna configurations have been constructed based on unique functional metasurfaces. In this article, we will review briefly the development roadmap of both metasurfaces and metasurface-based antennas, including antenna-inspired metasurfaces, metasurface-assisted antennas, and metasurface antennas. In particular, the recent fusion of metasurface and antenna as metantenna will bring significant impacts on methodologies of functional metasurface, antenna design, and radio-frequency device miniaturization.