## 1 Introduction
Few studies in the literature have focused on the design of cylindrical reflector antennas for space applications [18; 20; 21]. The offset parabolic-cylindrical reflector, detailed in [18], operates at a Ku-band of 13 GHz. Its feed source is an 8 \(\times\) 4 patch array antenna, and the aperture dimensions are 50 cm \(\times\) 50 cm (21.7\(\lambda\)\(\times\) 21.7\(\lambda\)). The resulting gain is recorded as 26.85 dBi. The authors of [20] introduced a deployable cylindrical reflector designed for low-Earth orbit satellites. Operating at 5.357 GHz, the antenna achieves a high gain of 42 dBi. It employs a 1 \(\times\) 32 element patch array feed to illuminate the large cylindrical aperture measuring 7 m \(\times\) 1.5 m (125\(\lambda\)\(\times\) 26.8\(\lambda\)). Despite its high gain, the structure is large, posing challenges in stowage to accommodate it within SmallSats. In [21], a linear feed array comprising 12 elements is employed to feed the cylindrical reflector with aperture dimensions of 140 cm \(\times\) 50 cm (10.2\(\lambda\)\(\times\) 3.9\(\lambda\)). The structure yields a medium gain of 11.2 dBi at 2.17 GHz. However, the gain and size of the reflector may not be appealing for CubeSats. Although C-band radar measurements have traditionally been utilized in sea ice remote sensing, research indicates that other frequency bands, notably the Ku-band, are effective in discerning snow and ice thickness [22; 23]. An effective Ku-band antenna must have high gain, low cross-polarization, a narrow beamwidth, and sufficient bandwidth to give usable on-ground image resolution. Few studies have addressed the use of cylindrical reflectors for space applications, and none have specifically proposed them for CubeSats. This paper outlines the design, construction, and testing of an offset cylindrical reflector antenna intended for low-Earth orbit observation, primarily focusing on monitoring Arctic snow and sea ice (shown in Figure 1) [24]. The microwave emissions from the Earth are collected by the antenna and is fed into the front-end of the radiometer. The brightness temperature measured by the radiometer is used to distinguish between sea ice, open water, and other features. The feed comprises an antenna array operating at a frequency of 17.2 GHz. The ratio of focal length to diameter of cylindrical reflector (\(F/D\)) is 0.65, chosen to achieve the desired reflector response while also maintaining the structural stiffness of the antenna. The feed is located along the axis of the cylindrical reflector, positioned at a distance \(F\) = 98 mm, and angled by 45\({}^{\circ}\) to illuminate the reflector. The developed reflector achieves a high gain of 25 dBi. Both the reflector and feed have been fabricated and measured, confirming a high degree of agreement between simulation and measured outcomes. The remainder of this paper is structured as follows: Section 2 offers comprehensive details on the design of the cylindrical reflector antenna, and the array feed design and its experimental validation. Section 3 presents the experimental results. Section 4 outlines the proposed deployable mechanism, while Section 5 concludes the paper.