Novel Load Bearing Antennas for CubeSat Applications

Increasingly, CubeSat and Small Satellite platforms are used for space exploration and Earth science remote sensing from LEO locations. Due to their low cost and fast deployment time, CubeSat platforms are also employed for new technology development and technology readiness level (TRL) maturation in the space environment. RF antennas are essential components of these CubeSat/Small Satellite platforms used for communication and remote sensing radars/radiometers. Types of antennas currently used on CubeSat/Small Satellite platforms include; monopole/dipole antennas; printed antennas; printed antennas integrated with a solar cell; and antennas printed on the backside of solar cell. These types of antennas need a packaging and deployment mechanism; hence, their use poses a deployment failure risk to a mission. Furthermore, these types of antennas add extra volume and weight to the payload. A novel load bearing antenna concept for CubeSat/Small Satellite platforms that does not need packaging or a deployment mechanism, thus eliminating the risk of deployment failure is presented

Design and Development of VHF Antennas for Space Borne Receivers for SmallSats

Space borne microwave remote sensors at VHF/UHF frequencies are important instruments to observe reflective properties of land surfaces through thick and heavy forestation on a global scale. One of the most cost effective ways of measuring land reflectivity at VHF/UHF frequencies is to use signals transmitted by existing communication satellites (operating at VHF/UHF band) as a signal of opportunity (SoOp) signal and passive receivers integrated with airborne/space borne platforms operating in the Low Earth Orbit (LEO). One of the critical components of the passive receiver is two antennas (one to receive only direct signal and other to receive only reflected signal) which need to have ideally high (\u3e30dB) isolation. However, because of small size of host platforms and broad beam width of dipole antennas, achieving adequate isolation between two channels is a challenging problem and need to be solved for successful implementation of space borne SoOp technology for remote sensing. In this presentation a novel enabling VHF antenna technology for Cubesat platforms is presented to receive direct as well as reflected signal with needed isolation. The novel scheme also allows enhancing the gain of individual channels by factor of 2 without use of reflecting ground plan

Direction-of-Arrival Estimation for Signal-of-Opportunity Receiver

In this presentation, a smart antenna technology for CubeSat platforms is developed that allows to maximize the gain of antenna system in a desired direction to interrogate selected target and minimize the antenna gain in other directions to suppress unwanted signals entering the receiver

Design VHF Antennas for Space Borne Receivers for SmallSats

Space borne microwave remote sensors at VHF/UHF frequencies are important instruments to observe reflective properties of land surfaces through thick and heavy forestation on a global scale. One of the most cost effective ways of measuring land reflectivity at VHF/UHF frequencies is to use signals transmitted by existing communication satellites (operating at VHF/UHF band) as a signal of opportunity (SoOp) signal and passive receivers integrated with airborne/space borne platforms operating in the Low Earth Orbit (LEO). One of the critical components of the passive receiver is two antennas (one to receive only direct signal and other to receive only reflected signal) which need to have ideally high (>30dB) isolation. However, because of small size of host platforms and broad beam width of dipole antennas, achieving adequate isolation between two channels is a challenging problem and need to be solved for successful implementation of space borne SoOp technology for remote sensing. In this presentation a novel enabling VHF antenna technology for Cubesat platforms is presented to receive direct as well as reflected signal with needed isolation. The novel scheme also allows enhancing the gain of individual channels by factor of 2 without use of reflecting ground plane

Study of Electromagnetic Scattering From Material Object Doped Randomly With Thin Metallic Wires Using Finite Element Method

A new numerical simulation method using the finite element methodology (FEM) is presented to study electromagnetic scattering due to an arbitrarily shaped material body doped randomly with thin and short metallic wires. The FEM approach described in many standard text books is appropriately modified to account for the presence of thin and short metallic wires distributed randomly inside an arbitrarily shaped material body. Using this modified FEM approach, the electromagnetic scattering due to cylindrical, spherical material body doped randomly with thin metallic wires is studied

Expandable and reconfigurable instrument node arrays

An expandable and reconfigurable instrument node includes a feature detection means and a data processing portion in communication with the feature detection means, the data processing portion configured and disposed to process feature information. The instrument node further includes a phase locked loop (PLL) oscillator in communication with the data processing portion, the PLL oscillator configured and disposed to provide PLL information to the processing portion. The instrument node further includes a single tone transceiver and a pulse transceiver in communication with the PLL oscillator, the single tone transceiver configured and disposed to transmit or receive a single tone for phase correction of the PLL oscillator and the pulse transceiver configured and disposed to transmit and receive signals for phase correction of the PLL oscillator. The instrument node further includes a global positioning (GPA) receiver in communication with the processing portion, the GPS receiver configured and disposed to establish a global position of the instrument node

Design and Development of VHF Antennas for Space Borne Signal of Opportunity Receivers for Cubesat Platforms

Design and Development of VHF Antennas for Space Borne Signal of Opportunity Receivers for Cubesat Platforms. Space borne microwave remote sensors at VHF/UHF frequencies are important instruments to observe reflective properties of land surfaces through thick and heavy forestation on a global scale. One of the most cost effective ways of measuring land reflectivity at VHF/UHF frequencies is to use signals transmitted by existing communication satellites (operating at VHF/UHF band) as a signal of opportunity (SoOp) signal and passive receivers integrated with airborne/space borne platforms operating in the Low Earth Orbit (LEO). One of the critical components of the passive receiver is two antennas (one to receive only direct signal and other to receive only reflected signal) which need to have ideally high (>30dB) isolation. However, because of small size of host platforms and broad beam width of dipole antennas, achieving adequate isolation between two channels is a challenging problem and need to be solved for successful implementation of space borne SoOp technology for remote sensing. In this presentation a novel enabling VHF antenna technology for Cubesat platforms is presented to receive direct as well as reflected signal with needed isolation. The novel scheme also allows enhancing the gain of individual channels by factor of 2 without use of reflecting ground plan

Modeling Electromagnetic Scattering From Complex Inhomogeneous Objects

This software innovation is designed to develop a mathematical formulation to estimate the electromagnetic scattering characteristics of complex, inhomogeneous objects using the finite-element-method (FEM) and method-of-moments (MoM) concepts, as well as to develop a FORTRAN code called FEMOM3DS (Finite Element Method and Method of Moments for 3-Dimensional Scattering), which will implement the steps that are described in the mathematical formulation. Very complex objects can be easily modeled, and the operator of the code is not required to know the details of electromagnetic theory to study electromagnetic scattering

Analysis of Fluid Gauge Sensor for Zero or Microgravity Conditions using Finite Element Method

In this paper the Finite Element Method (FEM) is presented for mass/volume gauging of a fluid in a tank subjected to zero or microgravity conditions. In this approach first mutual capacitances between electrodes embedded inside the tank are measured. Assuming the medium properties the mutual capacitances are also estimated using FEM approach. Using proper non-linear optimization the assumed properties are updated by minimizing the mean square error between estimated and measured capacitances values. Numerical results are presented to validate the present approach

RNAI AND MORPHOLINO AS TOOLS TO STUDY SIGNALING IN LIMULUS VENTRAL PHOTORECEPTORS.

ABSTRACT Title of Document: RNAI AND MORPHOLINO AS TOOLS TO STUDY SIGNALING IN LIMULUS VENTRAL PHOTORECEPTORS. Monika M Deshpande, Doctor of Philosophy, 2006 Directed By: Dr. Richard Payne, Neuroscience and Cognitive Science program Limulus ventral photoreceptors have been studied using electrophysiological, immunocytochemical, and biochemical techniques. However, genetic manipulation has eluded Limulus research because the animal takes about 10 years to mature. As an alternative, we decided to explore the possibility of using RNA interference (RNAi), and morpholino to reduce the levels of a target protein. The purpose of this study was to test whether use of these techniques would result in any physiological changes in the ventral photoreceptors. As a target we chose arrestin, a protein that binds to and quenches metarhodopsin, the activated form of rhodopsin. Injecting arrestin RNAi, or arrestin morpholino into the cells had a profound effect. The rate of spontaneous quantal events ('bumps') in the injected cells had a 5-fold increase as compared to bump rates of control cells at 24 hrs after injection. Because high levels of metarhodopsin are thought to be present in ventral photoreceptors even in darkness, this result is consistent with an increase in the amount of unquenched metarhodopsin in the cells. To show that the increase in spontaneous dark bumps was a result of unquenched metarhodospin, we treated RNAi -injected cells with hydroxylamine, a bleaching agent that destroys metarhodopsin. The bump rate after this treatment was down to pre-injection levels confirming our hypothesis that the excess bumps were generated by unquenched metarhodopsin. Another target protein selected was opsin. Opsin bound to the chromophore forms rhodopsin, and rhodopsin photoconverts to metarhodopsin. Therefore, opsin reduction was expected to lead to a reduction in sensitivity to light. sensitivity to light decreased by about 30 fold at 96 hrs after opsin morpholino injections. In another set of experiments, we fixed the injected cells with the arrestin/opsin antibodies. We measured the fluorescence from thee secondary antibodies targeted against the arrestin/opsin primary antibodies to get an insight into the protein levels. We observed a 2.5 fold decrease in fluorescent counts in arrestin morpholino injected cells and a 17 fold decrease in opsin injected cells