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Papers by Mahesh Abegaonkar

Tapered-CPW fed printed triangular monopole antenna

European Conference on Antennas and Propagation, 2006

A compact triangular monopole antenna fed by a tapered-coplanar waveguide (CPW) is presented. The... more A compact triangular monopole antenna fed by a tapered-coplanar waveguide (CPW) is presented. The simulated and measured return loss results are presented. The proposed antenna offers a wide bandwidth from 4.14¿9.84 GHz (81%) covering WLAN frequency bands for IEEE 802.11a and HiperLAN2 as is seen from the measured results.

Microwave and Optical Technology Letters, 2010

A band notched CPW UWB filter backed by rectangular rings is proposed.Initially, cascading of ape... more A band notched CPW UWB filter backed by rectangular rings is proposed.Initially, cascading of aperture-backed second-order microstrip filters is done to achieve the UWB passband. Later, to take advantage of the CPW geometry, the filter is converted to CPW configuration with rings at the back to achieve sharp cutoff characteristics and a notch at 5.1 GHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:950–954, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25088

Effect of Low-Intensity Microwave Radiation on Monoamine Neurotransmitters and Their Key Regulating Enzymes in Rat Brain

Cell biochemistry and biophysics, Jan 12, 2015

To compare the effects of different doses of microwave on the proliferative activity and cell cyc... more To compare the effects of different doses of microwave on the proliferative activity and cell cycle of cultured epithelial cells of rabbit lens, and to investigate the limit tolerant of microwave exposure. Cultured epithelial cells of rabbit lens were exposed to microwave radiation with frequency of 2,450 MHz and power density of 0.10, 0.25, 0.50, 1.00, 2.00 mW/cm(2) for 8 h in vitro. HE staining was used to observe the morphological changes of lens epithelial cells, the proliferative activity and cell cycle were measured by MTT assay and PI fluorescent staining. 8 h after radiation, 0.50, 1.00 and 2.00 mW/cm(2) microwave could decrease the proliferation of lens epithelial cells, make the cells disordered arrangement, shrinkage, detachment, and inhibit the synthesis of cell DNA. The percentage of G(0)/G(1) phase cells were 71.95% +/- 2.12%, 75.68% +/- 3.35% and 82.40% +/- 8.68% respectively, which were higher than that in control group (61.68% +/- 5.76%, P < 0.05 or P < 0.01). The percentage of S phase cells were 19.32% +/- 3.07%, 16.08% +/- 4.91% and 12.98% +/- 8.08% respectively, which were lower than that in control group (28.05% +/- 5.12%, P < 0.05 or P < 0.01). No obvious changes could be detected in 0.10, 0.25 mW/cm(2) microwave groups (P > 0.05). Microwave exceeding 0.50 mW/cm(2) may make injury to lens epithelial cells after 8 hour radiation, which may be related to the effect of microwave radiation on cell cycle.

Cognitive Impairment and Neurogenotoxic Effects in Rats Exposed to Low-Intensity Microwave Radiation

International journal of toxicology, Jan 5, 2015

The health hazard of microwave radiation (MWR) has become a recent subject of interest as a resul... more The health hazard of microwave radiation (MWR) has become a recent subject of interest as a result of the enormous increase in mobile phone usage. The present study aimed to investigate the effects of chronic low-intensity microwave exposure on cognitive function, heat shock protein 70 (HSP70), and DNA damage in rat brain. Experiments were performed on male Fischer rats exposed to MWR for 180 days at 3 different frequencies, namely, 900, 1800 MHz, and 2450 MHz. Animals were divided into 4 groups: group I: sham exposed; group II: exposed to MWR at 900 MHz, specific absorption rate (SAR) 5.953 × 10(-4) W/kg; group III: exposed to 1800 MHz, SAR 5.835×10(-4) W/kg; and group IV: exposed to 2450 MHz, SAR 6.672 × 10(-4) W/kg. All the rats were tested for cognitive function at the end of the exposure period and were subsequently sacrificed to collect brain. Level of HSP70 was estimated by enzyme-linked immunotarget assay and DNA damage was assessed using alkaline comet assay in all the groups. The results showed declined cognitive function, elevated HSP70 level, and DNA damage in the brain of microwave-exposed animals. The results indicated that, chronic low-intensity microwave exposure in the frequency range of 900 to 2450 MHz may cause hazardous effects on the brain.

Microstrip ring resonator as a moisture sensor for wheat grains

Microwave, MTT-S International Symposium, 1997

Microwave resonant frequency and quality factor of a ring resonator are measured with a single wh... more Microwave resonant frequency and quality factor of a ring resonator are measured with a single wheat grain as an overlay on the ring and are found to vary with the moisture content independent of the weight of the kernel.

2008 Asia-Pacific Microwave Conference, 2008

Frequency reconfigurable active antenna

2014 International Symposium on Antennas and Propagation Conference Proceedings, 2014

Parametric Study of a Parasitically-fed Broadband Monopole Patch Antenna

A monopole printed patch antenna parasitically fed by an inverted-L shaped monopole is proposed f... more A monopole printed patch antenna parasitically fed by an inverted-L shaped monopole is proposed for broadband applications in IEEE 802.11a/HiperLAN2 bands. The effect of various physical parameters, such as, dimensions of the parasitic element, coupling between inverted-L shaped monopole feed and the parasitic element is studied. A prototype antenna is fabricated with its dimensions optimized and its simulated and measured

Microwave and Optical Technology Letters, 2003

Microwave and Optical Technology Letters, 2008

Compact UWB bandpass filters using stub-loaded ring and triangular resonators fed with capacitive... more Compact UWB bandpass filters using stub-loaded ring and triangular resonators fed with capacitive-ended interdigital coupled lines are proposed. The proposed structures are fed with capacitive-ended interdigital coupled lines. The measured insertion loss for ring resonator filter is 1.0 dB and that for triangular resonator is 2.0 dB with corresponding group delays of 0.6 and 0.3 ns, respectively. These filters show sharp transitions at the edges of the UWB passband and improved out-of-band performance. The simulated and measured results are in good agreement and satisfy the FCC mask for indoor applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2917–2922, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23834

A Planar End-fire Array in S-band for Airborne Applications

IETE Journal of Research, 2012

ABSTRACT Planar end-fire arrays can be used in airborne radar applications for forward and rear v... more ABSTRACT Planar end-fire arrays can be used in airborne radar applications for forward and rear vision. The purpose of this work is to demonstrate the viability of constructing end-fire arrays with good bandwidth and front-to-back (f/b) ratio. The array so constructed must be extendable to a large number (possibly > 1 000) of elements depending on the platform. In this work, starting from a basic S-band 2x2 array, arrays with higher number of elements have been studied through simulations such as 4x4, 4x8, and 2x16 configurations. An end-fire array comprising 4x8 elements (uniformly excited) has been successfully fabricated and tested giving a f/b ratio of 15 dB, and directivity 15 dB and an array comprising 4x8 elements excited by coefficients of Chebyshev polynomials has been simulated which gives a f/b ratio of 25 dB and similar directivity. Beam steering simulations show that the 4x8 array can be steered to 25 degrees with acceptable side lobe levels.

Tapered-CPW fed printed triangular monopole antenna

European Conference on Antennas and Propagation, 2006

A compact triangular monopole antenna fed by a tapered-coplanar waveguide (CPW) is presented. The... more A compact triangular monopole antenna fed by a tapered-coplanar waveguide (CPW) is presented. The simulated and measured return loss results are presented. The proposed antenna offers a wide bandwidth from 4.14¿9.84 GHz (81%) covering WLAN frequency bands for IEEE 802.11a and HiperLAN2 as is seen from the measured results.

Microwave and Optical Technology Letters, 2010

A band notched CPW UWB filter backed by rectangular rings is proposed.Initially, cascading of ape... more A band notched CPW UWB filter backed by rectangular rings is proposed.Initially, cascading of aperture-backed second-order microstrip filters is done to achieve the UWB passband. Later, to take advantage of the CPW geometry, the filter is converted to CPW configuration with rings at the back to achieve sharp cutoff characteristics and a notch at 5.1 GHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:950–954, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25088

Effect of Low-Intensity Microwave Radiation on Monoamine Neurotransmitters and Their Key Regulating Enzymes in Rat Brain

Cell biochemistry and biophysics, Jan 12, 2015

To compare the effects of different doses of microwave on the proliferative activity and cell cyc... more To compare the effects of different doses of microwave on the proliferative activity and cell cycle of cultured epithelial cells of rabbit lens, and to investigate the limit tolerant of microwave exposure. Cultured epithelial cells of rabbit lens were exposed to microwave radiation with frequency of 2,450 MHz and power density of 0.10, 0.25, 0.50, 1.00, 2.00 mW/cm(2) for 8 h in vitro. HE staining was used to observe the morphological changes of lens epithelial cells, the proliferative activity and cell cycle were measured by MTT assay and PI fluorescent staining. 8 h after radiation, 0.50, 1.00 and 2.00 mW/cm(2) microwave could decrease the proliferation of lens epithelial cells, make the cells disordered arrangement, shrinkage, detachment, and inhibit the synthesis of cell DNA. The percentage of G(0)/G(1) phase cells were 71.95% +/- 2.12%, 75.68% +/- 3.35% and 82.40% +/- 8.68% respectively, which were higher than that in control group (61.68% +/- 5.76%, P < 0.05 or P < 0.01). The percentage of S phase cells were 19.32% +/- 3.07%, 16.08% +/- 4.91% and 12.98% +/- 8.08% respectively, which were lower than that in control group (28.05% +/- 5.12%, P < 0.05 or P < 0.01). No obvious changes could be detected in 0.10, 0.25 mW/cm(2) microwave groups (P > 0.05). Microwave exceeding 0.50 mW/cm(2) may make injury to lens epithelial cells after 8 hour radiation, which may be related to the effect of microwave radiation on cell cycle.

Cognitive Impairment and Neurogenotoxic Effects in Rats Exposed to Low-Intensity Microwave Radiation

International journal of toxicology, Jan 5, 2015

The health hazard of microwave radiation (MWR) has become a recent subject of interest as a resul... more The health hazard of microwave radiation (MWR) has become a recent subject of interest as a result of the enormous increase in mobile phone usage. The present study aimed to investigate the effects of chronic low-intensity microwave exposure on cognitive function, heat shock protein 70 (HSP70), and DNA damage in rat brain. Experiments were performed on male Fischer rats exposed to MWR for 180 days at 3 different frequencies, namely, 900, 1800 MHz, and 2450 MHz. Animals were divided into 4 groups: group I: sham exposed; group II: exposed to MWR at 900 MHz, specific absorption rate (SAR) 5.953 × 10(-4) W/kg; group III: exposed to 1800 MHz, SAR 5.835×10(-4) W/kg; and group IV: exposed to 2450 MHz, SAR 6.672 × 10(-4) W/kg. All the rats were tested for cognitive function at the end of the exposure period and were subsequently sacrificed to collect brain. Level of HSP70 was estimated by enzyme-linked immunotarget assay and DNA damage was assessed using alkaline comet assay in all the groups. The results showed declined cognitive function, elevated HSP70 level, and DNA damage in the brain of microwave-exposed animals. The results indicated that, chronic low-intensity microwave exposure in the frequency range of 900 to 2450 MHz may cause hazardous effects on the brain.

Microstrip ring resonator as a moisture sensor for wheat grains

Microwave, MTT-S International Symposium, 1997

Microwave resonant frequency and quality factor of a ring resonator are measured with a single wh... more Microwave resonant frequency and quality factor of a ring resonator are measured with a single wheat grain as an overlay on the ring and are found to vary with the moisture content independent of the weight of the kernel.

2008 Asia-Pacific Microwave Conference, 2008

Frequency reconfigurable active antenna

2014 International Symposium on Antennas and Propagation Conference Proceedings, 2014

Parametric Study of a Parasitically-fed Broadband Monopole Patch Antenna

A monopole printed patch antenna parasitically fed by an inverted-L shaped monopole is proposed f... more A monopole printed patch antenna parasitically fed by an inverted-L shaped monopole is proposed for broadband applications in IEEE 802.11a/HiperLAN2 bands. The effect of various physical parameters, such as, dimensions of the parasitic element, coupling between inverted-L shaped monopole feed and the parasitic element is studied. A prototype antenna is fabricated with its dimensions optimized and its simulated and measured

Microwave and Optical Technology Letters, 2003

Microwave and Optical Technology Letters, 2008

Compact UWB bandpass filters using stub-loaded ring and triangular resonators fed with capacitive... more Compact UWB bandpass filters using stub-loaded ring and triangular resonators fed with capacitive-ended interdigital coupled lines are proposed. The proposed structures are fed with capacitive-ended interdigital coupled lines. The measured insertion loss for ring resonator filter is 1.0 dB and that for triangular resonator is 2.0 dB with corresponding group delays of 0.6 and 0.3 ns, respectively. These filters show sharp transitions at the edges of the UWB passband and improved out-of-band performance. The simulated and measured results are in good agreement and satisfy the FCC mask for indoor applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2917–2922, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23834

A Planar End-fire Array in S-band for Airborne Applications

IETE Journal of Research, 2012

ABSTRACT Planar end-fire arrays can be used in airborne radar applications for forward and rear v... more ABSTRACT Planar end-fire arrays can be used in airborne radar applications for forward and rear vision. The purpose of this work is to demonstrate the viability of constructing end-fire arrays with good bandwidth and front-to-back (f/b) ratio. The array so constructed must be extendable to a large number (possibly > 1 000) of elements depending on the platform. In this work, starting from a basic S-band 2x2 array, arrays with higher number of elements have been studied through simulations such as 4x4, 4x8, and 2x16 configurations. An end-fire array comprising 4x8 elements (uniformly excited) has been successfully fabricated and tested giving a f/b ratio of 15 dB, and directivity 15 dB and an array comprising 4x8 elements excited by coefficients of Chebyshev polynomials has been simulated which gives a f/b ratio of 25 dB and similar directivity. Beam steering simulations show that the 4x8 array can be steered to 25 degrees with acceptable side lobe levels.