Kaushik Mandal

Bio: Kaushik Mandal is an academic researcher from University of Calcutta. The author has contributed to research in topics: Microstrip antenna & Antenna (radio). The author has an hindex of 14, co-authored 61 publications receiving 434 citations. Previous affiliations of Kaushik Mandal include Academy of Technology & Kalyani Government Engineering College.

High Gain Wide-Band U-Shaped Patch Antennas With Modified Ground Planes

Abstract: A high gain wideband U-shaped patch antenna with two equal arms on poly tetra fluoro ethylene (PTFE) substrate is presented. An inverted U-shaped slot is introduced on the circular or square shaped ground plane just under the U-shaped patch. In this communication the effect of size and shape of the ground plane on impedance bandwidth is studied. Maximum impedance bandwidth of 86.79% (4.5–11.4 GHz) is obtained with circular shaped ground plane with diameter 36 mm. The highest gain achieved is 4.1 dBi. The simulated results are confirmed experimentally. The proposed antenna is simple in structure compared to the regular stacked or coplanar parasitic patch antennas. It is highly suitable for wireless communications.

All-metal wideband metasurface for near-field transformation of medium-to-high gain electromagnetic sources

Abstract: Electromagnetic (EM) metasurfaces are essential in a wide range of EM engineering applications, from incorporated into antenna designs to separate devices like radome. Near-field manipulators are a class of metasurfaces engineered to tailor an EM source’s radiation patterns by manipulating its near-field components. They can be made of all-dielectric, hybrid, or all-metal materials; however, simultaneously delivering a set of desired specifications by an all-metal structure is more challenging due to limitations of a substrate-less configuration. The existing near-field phase manipulators have at least one of the following limitations; expensive dielectric-based prototyping, subject to ray tracing approximation and conditions, narrowband performance, costly manufacturing, and polarization dependence. In contrast, we propose an all-metal wideband phase correcting structure (AWPCS) with none of these limitations and is designed based on the relative phase error extracted by post-processing the actual near-field distributions of any EM sources. Hence, it is applicable to any antennas, including those that cannot be accurately analyzed with ray-tracing, particularly for near-field analysis. To experimentally verify the wideband performance of the AWPCS, a shortened horn antenna with a large apex angle and a non-uniform near-field phase distribution is used as an EM source for the AWPCS. The measured results verify a significant improvement in the antenna’s aperture phase distribution in a large frequency band of 25%.

A Design of a Dual-Band Bandpass Filter Based on Modal Analysis for Modern Communication Systems

Abstract: A dual-band bandpass filter (BPF) composed of a coupling structure and a bent T-shaped resonator loaded by small L-shaped stubs is presented in this paper. The first band of the proposed BPF covers 4.6 to 10.6 GHz, showing 78.9% fractional bandwidth (FBW) at 7.6 GHz, and the second passband is cantered at 11.5 GHz with a FBW of 2.34%. The bent T-shaped resonator generates two transmission zeros (TZs) near the wide passband edges, which are used to tune the bandwidth of the first band, and the L-shaped stubs are used to create and control the narrow passband. The selectivity performance of the BPF is analyzed using the transfer function extracted from the lumped circuit model verified by a detailed even/odd mode analysis. The BPF presents a flat group delay (GD) of 0.45 ns and an insertion loss (IL) less than 0.6 dB in the wide passband and a 0.92 IL in the narrow passband. A prototype of the proposed BPF is fabricated and tested, showing very good agreement between the numerically predicted and measured results.

Metamaterial based superstrate towards the isolation and gain enhancement of MIMO antenna for WLAN application

Abstract: This paper presents the implementation of metamaterial based superstrate inspired multiple input multiple output (MIMO) antenna with enhanced isolation and gain. Superstrate consist of novel hexagonal nested loop double negative (DNG) metamaterial is placed above the MIMO antenna and it exhibits isolation performance better than 24 dB over the entire WLAN band (5.68–6.05 GHz) with a remarkable peak gain of 7.98 dBi. Superstrate reduces the mutual coupling (MC) between the antenna elements by absorbing the near field component of the magnetic field. Reflection coefficient, transmission coefficient and radiation properties further confirm the performance of the proposed design for wireless applications. The prototype of the proposed design is fabricated and validated through measurement that shows good agreement with the simulation result.

Modelling of ultra-wide stop-band frequency-selective surface to enhance the gain of a UWB antenna

Abstract: Here, an ultra-wide stop-band single-layer frequency-selective surface (FSS) with high-incidence angle independence has been proposed to enhance the gain of an ultra-wideband (UWB) monopole antenna. The unit cell (0.2 λ × 0.2 λ ) of the proposed FSS consists of four asymmetric rectangular patches with circular slots embedded in it. This concept of four slotted patches is conceived to achieve ultra-wide stop-band characteristic over 4.7-14.9 GHz. An equivalent lumped circuit model for the FSS is proposed to provide insight into the working nature of the FSS. A UWB monopole antenna is also designed and integrated with the proposed FSS. Ultra-wide stop-band single-layer FSS converts the omnidirectional pattern of the monopole antenna into a unidirectional one and thereby registers a significant increase in its gain by 4.5 dBi. The design concept has been discussed and experimentally verified using simulated and measured results.

Response to FCC 98-208 notice of inquiry in the matter of revision of part 15 of the commission's rules regarding ultra-wideband transmission systems

Abstract: In general, Micropower Impulse Radar (MIR) depends on Ultra-Wideband (UWB) transmission systems. UWB technology can supply innovative new systems and products that have an obvious value for radar and communications uses. Important applications include bridge-deck inspection systems, ground penetrating radar, mine detection, and precise distance resolution for such things as liquid level measurement. Most of these UWB inspection and measurement methods have some unique qualities, which need to be pursued. Therefore, in considering changes to Part 15 the FCC needs to take into account the unique features of UWB technology. MIR is applicable to two general types of UWB systems: radar systems and communications systems. Currently LLNL and its licensees are focusing on radar or radar type systems. LLNL is evaluating MIR for specialized communication systems. MIR is a relatively low power technology. Therefore, MIR systems seem to have a low potential for causing harmful interference to other users of the spectrum since the transmitted signal is spread over a wide bandwidth, which results in a relatively low spectral power density.

Wideband and UWB Antennas for Wireless Applications: A Comprehensive Review

Abstract: A comprehensive review concerning the geometry, the manufacturing technologies, the materials, and the numerical techniques, adopted for the analysis and design of wideband and ultrawideband (UWB) antennas for wireless applications, is presented. Planar, printed, dielectric, and wearable antennas, achievable on laminate (rigid and flexible), and textile dielectric substrates are taken into account. The performances of small, low-profile, and dielectric resonator antennas are illustrated paying particular attention to the application areas concerning portable devices (mobile phones, tablets, glasses, laptops, wearable computers, etc.) and radio base stations. This information provides a guidance to the selection of the different antenna geometries in terms of bandwidth, gain, field polarization, time-domain response, dimensions, and materials useful for their realization and integration in modern communication systems.

Electromagnetic Bandgap Backed Millimeter-Wave MIMO Antenna for Wearable Applications

Abstract: A millimeter-wave (mm-Wave) multiple input multiple output (MIMO) antenna operating at 24 GHz (ISM band), suitable for wearable applications, is proposed in this paper. The proposed MIMO antenna consists of two elements, designed with an edge-to-edge distance of 5.14 mm, backed by a $5\times 5$ cell electromagnetic bandgap (EBG) structure. The antenna is fabricated on a flexible Rogers 6002 material ( $\epsilon _{r}=$ 2.94 , tan $\delta =$ 0.0012 , thickness = 0.254 mm ). The proposed antenna retains its performance when bent along the x-axis and y-axis. The performance of the antenna in term of s-parameters and radiation properties is studied in free space as well as on a human phantom. Good impedance matching of the antenna at the resonating frequency (24 GHz) is observed when it is bent and when worn on the body. The introduction of the EBG improves the gain by 1.9 dBi, reduces the backward radiation by 8 dB, reduces the power density on the back towards the body from > 200 W/m2 to < 10 W/m2, and also enhances the 10 dB bandwidth by 100 MHz. The antenna possesses a low envelope correlation coefficient (ECC) of 0.24, high diversity gain (DG) of 9.7 dB, reasonable multiplexing efficiency of −0.684 dB and a good peak gain of 6 dBi at 24 GHz. The proposed antenna is suitable for wearable applications at mm-Wave range due to its simple geometry and good performance in bending and on-body worn scenarios.

Wideband Four-Port MIMO antenna array with high isolation for future wireless systems

Abstract: A four-port MIMO antenna array with wideband and high isolation characteristics for imminent wireless systems functioning in 5G New Radio (NR) sub-6 GHz n77/n78/n79 and 5 GHz WLAN bands is proposed. Each array antenna element is a microstrip-line fed monopole type. The novelty of the antenna lies in loading an “EL” slot into the radiating element along with two identical stubs coupled to the partial ground in order to improve the impedance matching and radiation characteristics across the bands of interest. To further attain high port isolation without affecting the compactness and radiation performance of each antenna element, the technique of introducing an innovative un-protruded multi-slot (UPMS) isolating element (of low-profile 2 × 19 mm2) between two closely spaced antenna elements (with an edge-to-edge distance of approx. 0.03λ at 4.6 GHz) is also presented. Besides demonstrating a small footprint of 30 × 40 × 1.6 mm3, the proposed four-port MIMO antenna array has also shown wide 10-dB impedance bandwidth of 58.56% (3.20–5.85 GHz), high isolation of more than 17.5 dB, and good gain and efficiency of around 3.5 dBi and 85%, respectively, across the bands of interest. Finally, the MIMO performance metrics of the proposed antenna are also analyzed.