# Worldwide Coverage Mobile Systems for
## 4 Ku-Band Antennas Design Techniques
### Planar Antennas  
Figure 6 shows the panar antennas are an alternative antenna design which is based on the technique known as planar matrix. This kind of antennas is appropriate for mobile global coverage satellite reception due to its compact design, as compared to the aforementioned antennas, and the reduced visual impact. As the resulting flat antenna requires very little mounting space (it does not require an external LNB), it is preferred for those applications where the are physical limitations, i.e., there is no possibility of using larger antennas or in the case where regular satellite reception dishes antennas are not allowed by regulations, or in applications where the antenna must be transported. The most relevant advantage of this antenna is in the fact that it is the least annoying. It is important to highlight that the antenna will only provide a well-received signal level if it is located in the main area of the desired satellite coverage footprint area. In other words, it should be used in constellations where satellites transmit signal at high power. One of the main disadvantages of the planar matrix-based antenna is the limitation to the reception of a single satellite or a constellation of grouped satellites, like Astra, in 19.2\({}^{\circ}\) East or Hotbird in 13.0\({}^{\circ}\) East. Table 11 remarks the main features of this antenna. \begin{table}
\begin{tabular}{l c} \hline
**Feature** & **Value** \\ \hline Antenna diameter & 90 \(\times\) 99 cm \\ Antenna efficiency & 82\% \\ Cross polarization insulation & \(\leq\)\(-\)35 dB \\ VSWR & \(<\)1.12 \\ Beam width (3 dB) & 1.57\({}^{\circ}\) \\ \hline \end{tabular}
\end{table} 
Table 10: Features of the Gregory offset antenna. Figure 5: Double focus antenna—Offset Gregory. Figure 6: Planar antenna array: Ku-band, 16 \(\times\) 16, single circularly polarized (CP). In [21], the authors introduce the design of a wide-band antenna for Ku band satellite communications, at a centre frequency 11.725 GHz. The antenna is designed using the multilayer planar slot array technology and simulated to obtain a reference of the expected features. The designed array is composed of 16 \(\times\) 16 slot antennas elements, where each one is optimized by minimizing the return losses at the centre of the band. The design is intended to the reception of both orthogonal linear polarization. The antenna is aimed at receiving satellites signals from the Turksat, i.e., in the area around Turkey. For these satellites, the effective isotropic radiated power is about 54 dBw. The authors propose as design specification a minimum gain of 27 dBi for the whole antenna structure. In [22] the authors show the design and implementation of a planar Ku band antenna. The antenna is aimed at satellite communications and in particular, it's appropriate for receiving satellite TV channels in the Turkey region. The paper shows the key facts concerning the design and implementation stages. Furthermore, the main features of the antenna are measured to verify the results obtained in the simulation phase. A wide bandwidth multilayer patch antenna design and analysis are introduced in [23]. The wide bandwidth is achieved when stacking a patch over the fed patch, which is coupled in gap structure. The bandwidth of the constructed antenna based on layered patches is inverse to the gap size. Increasing the gain means decreasing the gap, and the construction of the antenna becomes more difficult and inaccurate. A test setup is performed in order to corroborate the simulation results. Table 12 shows the measured values of the main features of the antenna. In [24] the authors introduce a novel high gain patch antenna array that is based on a dual-band dual circularly polarized aimed at satellite communications for vehicle applications. To construct the array, a set of 16 linearly polarized dual-band elements where the array is backed with a new frequency-selective-surface-integrated artificial magnetic conductor ground, obtaining promising results.