## 1 Introduction  
The cellular communication system is the backbone of wireless communication and is widely used for transmission of data in the form of voices, images, and videos between users. The first generation called analogue systems have been evolved to second generation called digital systems. For the purpose of transmission of multimedia, third generation was introduced. By the introduction of high speed packet access (HSPA) and long term evolution (LTE) advanced, third generation (3G) is evolved to fourth generation (4G). The antenna systems and new technologies for designing antennas have also been developed and advanced in parallel with the evolution of mobile systems [1]. The current 4G system has been saturated because of limited bandwidth [2]. It is essential to improve the performance of the mobile network in terms of capacity to fulfill the future requirements of high-speed mobile networks [3; 4; 5; 6; 7]. Fifth generation (5G) is preferred over 4G owing to the availability of wide bandwidth which enhances network performance. Due to wider bandwidth, high volume data can be transferred in the form of tens of megabits per second (Mbps) to thousands of users simultaneously [8]. It reduces power consumption and provides improved spectral efficiency and enhanced coverage [9]. The usage of millimeter wave (mm wave) will improve the quality of the wireless communication system [10; 11; 12]. The 5G communication technology can provide many advantages due to its wider bandwidth, such as higher transmission rate, shorter latency, and higher capacity, over the current 4G system [13; 14]. After every ten years, a progressive change is experienced in mobile technology. Every new generation has brought improvement according to needs. The major factor is the need for high data rate which is experienced in the last ten years. A data rate of 15.4 Mbps will be required per subscriber using mobile phone which can support a very high resolution video (4K) having 4096 \(\times\) 2160 pixels [15]. This will enhance the video resolution, however, it will require a wider bandwidth [15]. The demand for access of bandwidth has been increased due to live streaming of watching videos for a long time by the users. The expected rise in traffic annually will reach to 291.8 exabytes (10\({}^{18}\) bytes) in near future [16]. Higher propagation losses are occurring in 5G mobile communications because wavelengths of mm waves are too short and have higher carrier frequency [17; 18; 19]. The short wavelengths are helpful in designing array antenna of many elements for obtaining high gain because small size of antenna is required for mm wave [20]. To minimize propagation losses, an antenna of stable radiation pattern, wideband, and high gain will be required. These goals can be achieved by employing Vivaldi antennas in the 5G communication systems. Vivaldi antennas have enormous advantages like its wider bandwidth, light weight, and easy to fabricate. Various techniques could be used for the improvement of gain, such as dielectric lens [21], metamaterial lens [22], and parasitic elliptical patch [23]. However, array structures are famous in Vivaldi antenna for aiming to achieve high gain. In this paper, a single element type-C antipodal Vivaldi antenna (AVA) is obtained by applying parametric analysis on type-A and type-B AVA antennas for aiming to cover the required bands. Type-C single AVA antenna covers wide range of Ku-bands from 14.34-20.98 GHz. This range includes 15 GHz and 18 GHz frequencies which can be used for Ku-band applications and may be used for 5G [24; 25; 26; 27; 28; 29; 30; 31; 32]. In addition to Ku-band, this antenna also covers (24.34-29 GHz) and (33-40 GHz) bands, in which 28 GHz and 38 GHz are considered candidate frequencies for future 5G communications [33; 34; 35]. Gain values obtained from singe element type-C AVA antenna are 2.5 dBi, 3.4 dBi, 3.6 dBi, and 7.4 dBi at the targeted frequencies of 15 GHz, 18 GHz, 28 GHz, and 38 GHz, respectively.