Moitreya Adhikary

Active Integrated Antenna Based Permittivity Sensing Tag

In this article, a novel negative resistance oscillator based active integrated tag antenna design is proposed for sensing material permittivity at a distance from the reader. A microstrip interdigital sensing arm acts as the terminating element of the oscillator. A broadband microstrip monopole tag antenna, working as the load element, is used to transmit the output signal of the oscillator to the reader. The frequency of oscillation varies with the permittivity of the loaded overlay dielectric substrate sample on the interdigital sensing arm. An oscillation frequency variation of 200MHz (6.8GHz to 7GHz) is experimentally observed for change in relative permittivity from 1 (unloaded) to 10.2. The proposed tag is calibrated, and it can measure relative permittivity of 1 to 12 with better than 3.6 accuracy. The permittivity of the loaded material can be calculated by measuring the output signal frequency of the active tag and utilizing frequency positioning algorithm. The phase noise of the stand-alone oscillator is measured to be better than 105dBcHz and 117dBcHz at 500KHz and 2MHz frequency offsets, respectively. The design is optimized theoretically and by simulation, and its proof-of-concept working principle is demonstrated experimentally. The proposed active sensor tag provides good reading range of about 600cm and consumes very low power (6mW). It has low profile (40cm

EMSICC-based compact array antenna having switchable frequency beam-scanning range in microstrip environment

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Miniaturized SIW filter antenna with loadable sensor for various microwave sensing applications

87cm), and it is suitable for low cost batch fabrication.

DRA with rat-race hybrid fed phemt differential lna for x-band receiver front-end application

In this paper, an eighth-mode substrate integrated circular cavity (EMSICC) based beam scanning array antenna having reconfigurable frequency band using PIN diodes is realized at X-band. A single annular complementary split ring resonator (CSRR) is introduced in ground plane of EMSICC and by rotating the ring, a shift of resonant frequency is obtained. Further, to implement the rotation, PIN diodes are incorporated at two positions and depending upon the switching states of these PIN diodes, a frequency-reconfigurable unit cell is designed. Finally, a beam scanning array antenna is designed utilizing that unit cell with reconfigurable frequency band. The band can be shifted by switching the diodes maintaining the scanning range of 36°.

SIW fed MIMO DRA for future 5G applications

In this paper, a novel substrate integrated waveguide (SIW) based filter antenna has been proposed for wireless sensor network applications. The proposed antenna consists of a fractal slot loaded miniaturized high-Q evanescent mode SIW bandpass filter section which provides a narrow pass band before the cut-off frequency of the unloaded SIW. A square patch monopole with partial ground plane, acting the radiating element, is cascaded to the filter. The sensor element can be integrated to the antenna on the slot area according to choice of applications. Depending on any measurable physical parameter, the dielectric constant of the sensor element changes and it affects the resonant frequency of the loaded filter antenna which can tune over a wide range. The antenna provides narrow band, high tuning range and easy integration to active circuits.

Planar miniaturized Substrate Integrated Waveguide triplexer with radial symmetry

In this paper, a novel balanced amplifier antenna has been proposed for X-band. The antenna module consists of a microstrip fed ground slot excited cylindrical dielectric resonator (CDR). The unbalanced antenna output is converted into balanced outputs by a 180 degree rat-race hybrid which feed a differential low noise amplifier (LNA) consisting of two cascade stages. A marchand balun type biasing arrangement is employed for the differential LNA to increase common mode rejection ratio (CMRR). The differential LNA provides peak differential gain of 30 dB, CMRR of 16.8 dB and 12.6% 3 dB FBW. The insertion gain of the hybrid fed LNA is about 21 dB, 3 dB FBW is 8.4% and overall noise figure of the system is about 4 dB. The CDRA has peak gain of 5.47 dBi. The proposed design is suitable for modern receiver front-end applications requiring balanced outputs.

Composite right/left-handed based compact and high gain leaky-wave antenna using complementary spiral resonator on HMSIW for Ku band applications

In this paper, a four element multiple-input multiple-output (MIMO) cylindrical dielectric resonator antenna (DRA) is presented. Each element of MIMO antenna system consists of substrate integrated waveguide (SIW) fed cylindrical DRA which are arranged such that MIMO configuration provides both spatial and polarization diversity to combat multipath fading. The proposed antenna is operating at 27.7 GHz with the simulated impedance bandwidth (|S11| < −10 dB) of 6.92% (26.64–28.55 GHz). The input port isolation is better than 27 dB throughout the operating bandwidth. For all the four excitation ports, the antenna radiates in broadside direction with peak gain ranging from 5.07–5.70 dBi over the operating band. The envelope correlation coefficient (ECC) is well below 0.0005 and channel capacity loss (CCL) is under 0.6 bits/sec/Hz in the desired band. The proposed antenna could be suitable for next generation 5G communication systems.

Air filled substrate integrated waveguide cavity backed slot antenna

In this paper a novel design technique for a planar highly miniaturized Substrate Integrate Waveguide (SIW) based triplexer has been proposed at C band. The proposed design employs evanescent mode propagation by placing a defected two pole resonating structure on the top layer of a waveguide section, which provides a pass-band at much lower frequency than the cut-off frequency of the unloaded waveguide. Three differently scaled defected structures on each radially symmetric waveguide section provide three distinct pass-bands. The triplexer is only 36mm (1.06λg) in diameter. The achieved fractional bandwidth is about 6%, the insertion loss is below 1dB and the isolation between the three ports is more than 18 dB. The structure provides miniaturization, low loss, high isolation and good out of band performance. Also it is planar, less bulky and easy to fabricate.