## 3 Results
A summary of the antenna is presented in Figure 7.0 The performance of the proposed antenna was compared with existing UHF antennas, tabulated in Figure 7.1 Considering the comparison criteria in the lower UHF band, it can be seen that the proposed antenna was a potential candidate for the nanosatellite communication system. Figure 7.2 (**a**) Solar output power and short circuit current measurement without and with antenna placement; (**b**) Solar characterization with varying antenna power from 0.1 W to 0.5 W. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Specifications** & **Unit** \\ \hline Frequency & 447.5–453.5 & MHz \\ Impedance bandwidth (\(-10\) dB) & 6 & MHz \\ Polarization & Linear & - \\ Realized Gain & 0.6 & dB \\ Antenna Size & 80 \(\times\) 90 & mm \\ Efficiency & 67.45 & \% \\ Material & Brass & - \\ RF input & 50 \(\Omega\) mmcx connector & - \\ Vibration Test & Qualified & - \\ \hline \hline \end{tabular}
\begin{tabular}{c c c} \hline \hline
**RF: radio frequency.** \\ \end{tabular}
\end{table} 
Table 2: Summary of the proposed ultra-high frequency (UHF) antenna. Figure 12: Vibration test setup of the proposed antenna with nanosatellite structure. Aluminum 7075 material based 2U nanosatellite structure was considered for the test as 100+ / – 0.1 mm wide (+X, +Y axes); 227+ / – 0.1 mm tall (+Z axis) and maximum weight was 2.6 kg. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Ref. No.** & **Antenna Type** & \begin{tabular}{c} **Operating** \\ **Frequency (MHz)** \\ \end{tabular} & \
\begin{tabular}{c} **Antenna Size** \\ **(mm)** \\ \end{tabular} & **Gain** &
\begin{tabular}{c} **Solar Integration** \\ **Facility** \\ \end{tabular} & **Remarks** \\ \hline
[19] & Printed patch & 410–485 & \(220\times 220\times 28.5\) & 5.2 dB & no & Too large for 1U, 2U nanosatellites. \\ \hline
[20] & Microstrip patch & 435–437 & \(170\times 120\times 6.4\) & 0.7 dB & no & Too large to fit with 1U \\  & & & & & & & \\
[21] & Fractal shaped & 700–4710 & \(120\times 120\times 1.6\) & 1.71 dB & no &
\begin{tabular}{c} Not compact enough. Does \\ not cover lower UHF \\ frequency (450 MHz) \\ \end{tabular} \\ \hline
[14] & Printed patch & 427.38–437.17 & \(320\times 80\times 3.17\) & 2.12 dB & no & Large dimension \\ \hline
[22] & Microstrip patch & 384–410 & \(150\times 150\times 37\) & 0.4 dB & no &
\begin{tabular}{c} Low gain with large \\ dimension. \\ \end{tabular} \\ \hline
[23] & Dipole & 430 & 160 & 2.15 dB & yes &
\begin{tabular}{c} Externally mounted with \\ satellite structure \\ \end{tabular} \\ \hline
[24] & Monopole & 435–438 & 175 & 2.35 dBi & yes & Deployable complexity \\ \hline
[25] & Monopole & 146 \& 438 & \(513.6\times 10\times 10\) & \
\begin{tabular}{c} 2.06 dB at \\ 146 MHz \\ 3.35 dBi at \\ 438 MHz \\ \end{tabular} & yes & Deployable complexity \\ \hline
\begin{tabular}{c} Proposed \\ Antenna \\ \end{tabular} & Modified PIFA & 447.5–453.5 & \(80\times 90\times 0.5\) & 0.6 dB & yes & Deployable complexity free \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison of Characteristics of Different UHF antennas. The proposed design provides a significant trade-off between the antenna size and performance in terms of gain, efficiency and operating band. In context of deployment, nanosatellite engineers have to go through complexities for the design and operation of the deployment mechanism. Certainly, the proposed antenna has the potential to provide deployment-free operation and this allows the satellite engineers to focus on other design criteria. The amount of gain provided by the antenna is satisfactory for smooth uplink and downlink communication in the UHF band. Moreover, the gain achieved by the antenna is measured while antenna is integrated with the nanosatellite structure. So, there is no risk of decreasing the gain after integration with the nanosatellite structure that usually happens in patch antennas. There are commercially available UHF nanosatellite antennas that have approximately 0 dB gain [26].