Guy Seguin

Coplanar-waveguide-fed slot-coupled rectangular dielectric resonator antenna

A novel coupling scheme to a rectangular dielectric resonator antenna is proposed and investigated. In particular, coupling to the resonator is achieved through a narrow slot at the end of a coplanar waveguide (CPW). The objectives of this design are to maximize the coupling, match the dielectric resonator to the CPW feed line, achieve resonance at the desired frequency, obtain linear polarization with low cross polarization components, and minimize back radiation without using a back conductor. An approximate and quick design approach is given followed by more accurate design and analysis using commercial software. The antenna was fabricated and tested. Measurements match well with simulation results.

Dual-band dual-polarized perforated microstrip antennas for SAR applications

For dual-band dual-polarized synthetic aperture radar (SAR) applications a compact low-profile design is investigated. The operating frequencies are in the L and C-bands, centered about 1.275 and 5.3 GHz, respectively. Since the C-band frequency is larger by a factor of four, its array elements and inter-element separations are smaller by the same ratio. Thus, to allow similar scan ranges for both bands, the L-band elements are selected as perforated patches to enable the placement of C-band elements within them. Stacked-patch configurations were used to meet the bandwidth requirements, especially in the L-band. The C-band element was designed numerically, but the perforated L-band one required final experimental optimization. Also, in the latter case of L-band, a balanced transmission line feed was used to minimize cross polarization. For the C-band elements, slot coupling was used and, to simplify the feed, symmetric parasitic slots were incorporated to minimize cross polarization. No vertical connections were utilized, and electromagnetic couplings resulted in a compact low-profile design, with an electrically and thermally symmetric geometry.

Modified waveguide model (MWGM) for rectangular dielectric resonator antenna (DRA)

Based on the concept of effective dimensions, a modification to the conventional waveguide model (CWGM), usually used to predict the resonant frequency of rectangular DRA, is introduced. Compared with the experimental results, it is found that this newly introduced MWGM yields more accurate results for the resonant frequency than the CWGM. Accuracy of the results is also checked by comparison with numerically calculated values using a TLM-based commercial software. It is also found that the MWGM not only yields accurate values, but also results in considerable computation time savings.xa0© 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 19: 158–160, 1998.

Multi-frequency and multi-polarization SAR system analysis with simulation software developed at CSA

The multi-frequency and multi-polarization SAR simulator developed at the Canadian Space Agency (CSA) is aimed to study an advanced SAR system performance in the simulated SAR images. This simulator is designed either as a SAR system simulator which concentrates on the radar system and SAR processing techniques, or as a SAR image product simulator which focuses on a target model and a radar backscattering model, so as to understand SAR polarization characteristics completely. The paper presents the simulation approach of a point target model and a distributed target model for spaceborne SAR which is adopted in the authors simulator. The current results are given and the status of the SAR simulator software is addressed.

Radarsat Constellation, moving toward implementation

The Canadian Space Agency initiated the development of a three-satellite SAR mission, known as the RADARSAT Constellation Mission (RCM), in 2005. The main objective of the mission is to assure C-band data continuity in the next decade, while allowing a greater use of data for operational applications by providing more persistent observation over Canada and better system reliability. The Phase B contract was awarded in November 2008 for a period of 16 months. The Space and Ground Segment Requirements reviews were held at the end of February 2009. The spacecraft and Ground Segment concepts were adopted and design decisions have been taken to allow preliminary design to proceed. A Payload and Bus Preliminary Design reviews were held in Fall 2009. A Mission Preliminary Design review was held in February 2010. The CSA is currently in phase C and preparing for the Critical Design Review. Several challenges, such as the implementation of the ship detection mode or the final selection of the launcher must be resolved and important decisions must be taken to allow the progress of the program toward full implementation. The first spacecraft will be built and tested as a proto-flight and launched in 2014. The following two spacecrafts will then be built and tested in parallel and launched in 2015.

Next generation SAR

Canadas RADARSAT initiative has demonstrated the utility of SAR data and whetted the appetite for further data sources and products. The market has now been stimulated and is starting to grow. Canadian Industry is uniquely placed to benefit from its involvement in what is currently the only commercial operational SAR system. The ongoing development of key technologies is fundamental to Canadian Industries ability to maintain and exploit our current world leading status in SAR remote sensing. In order to maintain Canadas leadership and carry on the commercial exploitation of SAR remote sensing it is essential to develop a new generation of SAR Spacecraft that are responsive to evolving user needs. This paper describe the Canadian Space Agency “Next generation SAR” technology development program, proposed for the Long Term Space Plan III. This program is considered as essential to provide the necessary technological development to support a Government decision regarding future RADARSAT missions to guarantee continuous availability of RADARSAT data in the next decade.

Caribbean Satellite Disaster Pilot: A CEOS activity for GEO in support of GEOSS

The Caribbean Satellite Disaster Pilot (CSDP) was established in 2009 under the Group on Earth Observations (GEO) 2009-2011 work plan. It was implemented through the Committee on Earth Observation Satellites (CEOS) 2009-2011 Action Plan under USA National Aeronautics and Space Administration (NASA) leadership with strong support from the Caribbean Disaster and Emergency Management Agency (CDEMA), the Canadian Space Agency (CSA), the Caribbean Institute for Meteorology and Hydrology (CIMH) the Water Center for the Humid Tropics of Central America and the Caribbean (CATHALAC), and the University of West Indies (UWI). It aims to demonstrate the effectiveness of satellite data for full cycle disaster management by identifying and implementing specific applications and products and addressing endemic training and capacity building issues in the region. The project is entering the final year of its demonstration phase before beginning operational implementation of its key services in 2013.

RADARSAT constellation, project objectives and status

The RADARSAT Constellation is an evolution of the RADARSAT program with the objective of assuring C-band data continuity in the next decade with improved operational use of Synthetic Aperture Radar (SAR) and improved system reliability. This paper describes missions main objectives and user requirements, as well as its concept and current status.

The RADARSAT constellation payload design

The Canadian Space Agency completed the definition phase of the RADARSAT Constellation, a constellation of three satellites that will ensure C-band data continuity with RADARSAT-2. The first satellite is scheduled to enter in operation toward the end of the RADARSAT-2 mission, for a full implementation of the constellation in 2014-15. The RADARSAT Constellation is designed to improve significantly the availability of SAR data for main Canadian Government departments, the main applications areas being maritime surveillance, ecosystem monitoring and disaster management. An important constraint on the mission was to reduce significantly the cost of SAR data, which forced the use of new approaches in the payload design. The paper presents the initial payload design process and three techniques investigated to improve its performance.

Integrated beam synthesis and performance analysis of a spaceborne SAR antenna

A set of tools to accomplish beam synthesis for synthetic-aperture radar antennas is presented. The synthesis process optimizing the beam properties is guided by criteria of the radar performance in terms of range ambiguities and noise-equivalent backscattering coefficient. The tools implemented with MATLABP are validated with examples of beams generated by RADARSAT