Department of Electrical Engineering

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IIT Jodhpur

In this paper, the design of Half-Mode Substrate Integrated Waveguide (HMSIW) fed dual frequency microstrip patch antenna has been presented. The proposed antenna is designed using two microstrip patches such that it resonates at two frequencies 9.95 GHz and 11.35 GHz which are used for X-band applications. The HMSIW is excited to generate dominant TE10HM mode. Two patches are used as a radiating elements fed by the open end of HMSIW. The bandwidth at 9.95 GHz is 320 MHz (3.22%) with the return loss of -20 dB and the bandwidth at 11.35 GHz is 580 MHz (5.16%) with the return loss of -30 dB have been achieved. © 2016 IEEE.

World University root node

2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016 - Proceedings

Design of HMSIW fed dual frequency microstrip patch antenna for X-band applications

In this paper, a design of Substrate Intergrated Waveguide (SIW) Phase Shifter is designed by placing multiple rows of air holes in a single substrate which modifies effective dielectric constant of the material and as a result, the phase of the propagating wave is modified while maintaining insertion loss less than 0.8 dB. The proposed design operates in X band (8-12 GHz) having reflection coefficient better than -15 dB within a band of 3 GHz (31.5%) and a phase shift of 24.8°±4.7° throughout the operating band. © 2015 IEEE.

2015 IEEE Applied Electromagnetics Conference, AEMC 2015

Design of planar substrate integrated waveguide (SIW) phase shifter using air holes

Single-mode-multimode-multimode (SMm) fiber structure provides an all-fiber solution for exciting a single radial mode in a multimode fiber (MMF). The proposed SMm design essentially exploits the interfering modes of the first MMF for exciting a single mode in the second. In this paper, the sensitivity of single-mode quality to small variations in the fiber parameters and geometrical misalignments is studied in detail. Different methods are suggested to mitigate the mode quality degradation caused by errors in the fiber parameters. An estimate of the acceptable geometrical misalignments in the structure is also given for achieving a high-quality single mode from the device. © 2016 Optical Society of America.

Journal of the Optical Society of America B: Optical Physics

Single-mode-multimode-multimode device: Sensitivity of the single mode to the fiber parameters and geometrical misalignments

The patterning of thin films play major role in the performance of MEMS devices. The wet etching gives an isotropic profile and etch rate depends on the temperature, size of the microstructures and repetitive use of the solution. Even with the use of selective etchants, it significantly attacks the underlying layer. On the other side, dry etching is expensive process. In this paper, double layer of photoresist is optimized for lift-off process. Double layer lift-off technique offers process simplicity, low cost, over conventional single layer lift-off or bilayer lift-off with LOR. The problem of retention and flagging is resolved. The thickness of double coat photoresist is increased by 2.3 times to single coat photo resist. © 2016 Author(s).

AIP Conference Proceedings

Low cost lift-off process optimization for MEMS applications

This paper reports a low power miniaturized MEMS based integrated gas sensor with 36.84 % sensitivity (ΔR/R0) for as low as 4 ppm (NH3) gas concentration. Micro-heater based gas sensor device presented here consumes very low power (360 °C at 98 mW/mm2) with platinum (Pt) micro-heater. Low powered micro-heater is an essential component of the metal oxide based gas sensors which are portable and battery operated. These micro-heaters usually cover less than 5 % of the gas sensor chip area but they need to be thermally isolated from substrate, to reduce thermal losses. This paper elaborates on design aspects of micro fabricated low power gas sensor which includes ‘membrane design’ below the microheater; the ‘cavity-to-active area ratio’; effect of silicon thickness below the silicon dioxide membrane; etc. using FEM simulations and experimentation. The key issues pertaining to process modules like fragile wafer handling after bulk micro-machining; lift-off of platinum and sensing films for the realization of heater, inter-digitated-electrodes (IDE) and sensing film are dealt with in detail. Low power platinum microheater achieving 700 °C at 267 mW/mm2 are fabricated. Temperature calculations are based on experimentally calculated thermal coefficient of resistance (TCR) and IR imaging. Temperature uniformity and localized heating is verified with infrared imaging. Reliability tests of the heater device show their ruggedness and repeatability. Stable heater temperature with standard deviation (σ) of 0.015 obtained during continuous powering for an hour. Cyclic ON–OFF test on the device indicate the ruggedness of the micro-heater. High sensitivity of the device for was observed for ammonia (NH3), resulting in 40 % response for ~4 ppm gas concentration at 230 °C operating temperature. © 2015, Springer-Verlag Berlin Heidelberg.

Microsystem Technologies

Low power highly sensitive platform for gas sensing application

An analysis of power supply induced jitter in a high speed serial link is presented in this paper. An equivalent reduced model for serial link is used for the analysis. Jitter induced by the ripples in power delivery network is analyzed by a small signal equivalent model. The effect is modeled by a transfer function which is not technology specific and can be used generically for System-On-Chip (SoC) level design considerations. The analysis is supported by experimental results by simulation in 130nm BiCMoS RF technology and 28nm FDSOI technology (both technologies are of STMicroelectronics). © 2015 IEEE.

International System on Chip Conference

Analysis of a serial link for power supply induced jitter

In this letter, a novel coaxial line to substrate integrated waveguide (SIW) broadband transition is presented. The transition is designed by connecting the inner conductor of a coaxial line to an open-circuited SIW. The configuration directly transforms the TEM mode of a coaxial line to the fundamental TE10 mode of the SIW. A prototype back-to-back transition is fabricated for X-band operation using a 0.508 mm thick RO 4003C substrate with dielectric constant 3.55. Comparison with other reported transitions shows that the present structure provides lower passband insertion loss, wider bandwidth and most compact. The area of each transition is 0.08λg2 where λg is the guided wavelength at passband center frequency of f0= 10.5 GHz. Measured 15 dB and 20 dB matching bandwidths are over 48% and 20%, respectively, at f0. © 2001-2012 IEEE.

IEEE Microwave and Wireless Components Letters

A Compact Broadband Direct Coaxial Line to SIW Transition

A dual-beam substrate integrated waveguide (SIW) periodic leaky wave antenna (LWA) is designed and fabricated. The dual-beam operation is obtained by using leakage from the side walls of the SIW. The two beams are mirror image of each other. The feeding arrangement is simple and the antenna as a whole is easy to fabricate. A backward end fire to forward end fire scanning range of almost 74° is obtained by varying frequency from 8.5GHz to 13.3GHz. Side lobe level is better than 13dB in the specified frequency range. Measurement results match well with simulated results. © 2015 IEEE.

Proceedings of the 2015 International Conference on Microwave and Photonics, ICMAP 2015

Dual-beam substrate integrated waveguide periodic leaky-wave antenna

Wireless and power line communication (PLC) technologies form an important aspect of signal processing for communications in smart grids. This paper provides the performance evaluation of a decode-And-forward based dualhop wireless-powerline mixed cooperative system in terms of analytical average bit error rate (BER). The fading in the wireless channel is modeled by the Nakagami- distribution while that in the PLC channel is modeled using the Log-Normal distribution. The analysis involving Log-Normal fading is very complicated; hence, we use the gamma approximation to Log- Normal distribution for our analysis. The additive noise in PLC channel follows Bernoulli-Gaussian distribution. We derive probability density function of end-To-end signal-To-noise ratio of the considered system. A closed-form expression of the average BER of the considered system is computed. We also evaluate the diversity of the considered system. Validity of the derived analytical expressions is closely verified by simulated results. Index Terms- Bernoulli-Gaussian process, bit error rate, decode-And-forward, Log-Normal distribution, Nakagami-fading. © 2016 IEEE.

International Conference on Advanced Technologies for Communications

Performance of a dual-hop wireless-powerline mixed cooperative system

In this paper, a novel excitation technique by a commercially available SMA connector is presented for the empty substrate integrated waveguide (ESIW). The SMA connector is directly connected to one end of the ESIW. A prototype back-to-back transition is designed and fabricated for X-band operation. Measurement results show that the insertion loss of the back-to-back transition is below 1 dB over 7.15 GHz to 12.5 GHz. Losses from the transition are studied in details. The transition has a compact dimension of 22 mm × 3.5 mm. © 2015 IEEE.