**5. Technical features and development of spaceborne SAR plane reflector metasurface phased array antenna**

The Capella X-SAR satellite constellation plan is a constellation plan proposed by Capella Space, which consists of 36 spaceborne SAR systems. 36 SAR satellites form 12 orbital planes, each operating in a 500 km polar orbit with an orbital period of 90 min, providing average imaging revisit time of less than 1 h. Capella's 01 star Denali was launched as a test star in December 2018. The star uses an "origami-type" planar reflector metasurface antenna (as shown in **Figure 18** left). The launch time of subsequent stars is shown in **Table 2**. It is a meshed reflector antenna with a peripheral frame structure (as shown in **Figure 18** right) [59].

Capella's 01 satellite, Denali, was launched as a test satellite, which is the size of a backpack and has a mass of about 40 kg. When designing Denali's SAR payload, the researchers combined an origami-shaped antenna with efficient electronics. Among

**Figure 18.** *Plane reflector metasurface array antenna of Capella X-SAR plan.*


**Table 2.** *Capella X-SAR plan.*

*The Present Situation and Development for Spaceborne Synthetic Aperture Radar Antenna… DOI: http://dx.doi.org/10.5772/intechopen.106040*

**Figure 19.** *Example of array antenna of Capella satellite.*

them, the antenna is made of flexible material, and the area is about 8 m<sup>2</sup> after deployment. Columns 3 and 4 in **Figure 19** are the dimensions of the Denali satellite before and after deployment [60].
