## 2 Components for the Testing
### Antennas under Study
#### 2.1.1 Linearly Polarized Antenna Booster  
The antenna booster for the linear polarization device had the dimensions of 7.0 \(\times\) 3.0 \(\times\) 2.0 mm\({}^{3}\) and was centered at a frequency of 1575 MHz (Table 1). This radiates evenly because of its omnidirectional emission pattern. The peak gain for this antenna was 1.8 dBi. Figure 1 depicts the 53 \(\times\) 53 mm\({}^{2}\) device and the GPS antenna booster positioned at the top left corner of the PCB [21].  
The LNA used for these measurements was an external LNA attached to the device with SMA transitions, which introduces losses. This LNA had a gain of 16.5 dB, a noise figure of 1.03 dB, and was centered at 1575 MHz (Table 2).  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Antenna Booster** & **Microstrip Antenna** \\ \hline Frequency & 1575 MHz & 1575.42 \(\pm\) 1.023 MHz \\ Dimensions & 7.0 \(\times\) 3.0 \(\times\) 2.0 mm\({}^{3}\) & 17.0 \(\times\) 4.0 mm\({}^{3}\) \\ Peak Gain & \(-\)2.1 dBi Typ. @ Zenit & \(-\)1.0 dBi Typ. @ Zenit \\ Polarization & Linear & RHCP \\ Radiation pattern & Omnidirectional & NE \\ Impedance & 50 \(\Omega\) & 50 \(\Omega\) \\ \hline \hline \end{tabular} \({}^{\dagger}\) Only the ceramic patch was included in this measurement; the patch size was 17.0 \(\times\) 17.0 \(\times\) 6.1 mm\({}^{3}\).  
\end{table}
Table 1: Linearly polarized antenna and circularly polarized antenna specifications.  
Figure 1: A 53 \(\times\) 53 mm\({}^{2}\) PCB with a linearly polarized GPS antenna booster. A ground plane was printed over the FR4 substrate (1 mm thick, \(\epsilon_{\mathrm{r}}\) = 4.15, \(\mathrm{tan}\delta\) = 0.017). The chip antenna booster component on the right operated at 698–960 MHz and 1710–2170 MHz. The GPS antenna booster was 7 \(\times\) 3 \(\times\) 2 mm\({}^{3}\). [S] represents the S\({}_{11}\) for each antenna booster without a matching network.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Antenna Booster** & **Microstrip Antenna** \\ \hline Frequency & 1575.42 MHz & 1575.42 MHz \\ Gain & 16.5 dB \({}^{1}\) & 16 dB \({}^{1}\) \\ Noise figure & 1.03 dB & 2.5 dB \\ \hline \hline \end{tabular} \({}^{\dagger}\) Two RF transitions used for the antenna booster setup had insertion losses of 0.15 dB. This justifies the 0.5 dB extra gain in the LNA.  
\end{table}
Table 2: LNA (low noise amplifier) is used in both devices.  
Additionally, to model a more realistic scenario, an antenna booster-based chip component was placed at the right corner of the PCB, operating at cellular frequency bands comprising 698-960 MHz and 1710-2170 MHz. The objective was to consider a real situation, such as a tracking device having cellular connectivity (ex. LTE-M) and GPS (Figure 1).  
Since the 7 \(\times\) 3 \(\times\) 2 mm\({}^{3}\) GPS antenna booster is non-resonant at the frequency bands of operation, a matching network with lumped components (SMD 0402) was designed [1]. Due to the narrow bandwidth needed for GPS (1.5%), the matching network was simple, comprising only three lumped components, a series, and a shunt inductor (Figure 1). The measured total efficiency (\(\eta_{\mathrm{t}}=\eta_{\mathrm{r}}\cdot(1-1S_{11})^{2}-1S_{21}\,|^{2}\)) takes into account all losses of the antenna system (antenna booster, FR4 of the PCB, feeding line, and matching network), the matching at the GPS port (\(S_{11}\)), and the coupling between the GPS and cellular port (\(S_{21}\)). This total efficiency was measured using 3D-pattern integration with an MVG Star-Lab anechoic chamber resulting in a total efficiency of 75% at 1575 MHz. Note that antenna booster technology can also operate for other radio protocols from a single frequency band to multiband operation [1; 2]. For multiband operation, a multiband matching network was designed that can be easily addressed through matching network synthesis [1]. For example, operation across 824-960 MHz and 1710-2690 MHz can be achieved with a tiny antenna booster of only \(\lambda/30\) at 824 MHz.