## 10 Conclusion  
Active wearable BANs may be used in receiving or transmitting channels. In transmitting channels, a power amplifier is connected to the antenna. In receiving channels, a low noise amplifier is connected to the receiving antenna.  
Ultra-wideband passive and active printed slot antenna may be employed in wideband wearable IoT and 5G communication systems. The active slot antenna gain and noise figure are summarized in Table 5.  
The antennas presented in this paper are low-cost wideband passive and active antennas for receiving and transmitting wearable IoT and 5G communication systems for medical application.  
Wearable technology provides a powerful new tool to medical and surgical rehabilitation services. Wearable body area network, WBAN, is emerging as an important option for medical centers and patients. Wearable technology provides a convenient platform that may quantify the long-term context and physiological response of individuals. Wearable technology will support the development of individualized treatment systems with real-time feedback to help promote patients' health. Wearable medical systems and sensors can measure body temperature, heartbeat, blood pressure, sweat rate, perform gait analysis, and other physiological parameters of the person wearing the medical device.  
Figure 7: **(a) A wideband active receiving wearable slot antenna; (b) Active T shape slot antenna S11 parameter; (c) S11 of the T shape wearable slot attached to a 1 mm shirt with \(\varepsilon_{r}\) = 2.2 on human body; (d) Active T shape slot antenna S21 parameter; (e) Active slot antenna noise figure.**  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Antenna** & **Frequency (GHz)** & **VSWR** & **Gain (dB)** & **Noise Figure (dB)** \\ \hline Loop & 0.45 & 4:1 & 0 & – \\ Active receiving loop & 0.35–0.58 & 2:1 & 25 \(\pm\) 2.5 & 0.7 \(\pm\) 0.2 \\ Active Rx. dual polarized antenna & 0.38–0.68 & 2:1 & 25 \(\pm\) 2.5 & 1 \(\pm\) 0.5 \\ Active Tr. dual polarized antenna & 0.38–0.6 & 3:1 & 14 \(\pm\) 3 & – \\ Active transmitting loop antenna & 0.36–0.6 & 3:1 & 13 \(\pm\) 3 & – \\ T shape slot & 1–3 & 2:1 & 3 & – \\ Active Rx. T slot & 0.2–0.58 & 3:1 & 18 \(\pm\) 2.5 & 0.5 \(\pm\) 0.3 \\  & 1–3 & 2:1 & 12.5 \(\pm\) 2.5 & \\ \hline \hline \end{tabular}
\end{table}
Table 5: Comparison and summary of electrical parameters of wearable antennas.  
Gait analysis is a useful tool both in clinical practice and biomechanical research. Gait analysis using wearable sensors provides quantitative and repeatable results over extended time periods with low cost and good portability, showing better prospects and making great progress in recent years. At present, commercialized wearable sensors have been adopted in various applications of gait analysis.  
The active transmitting loop antenna and dual polarized antenna output power is around 18 dBm. A comparison and summary of electrical parameters of the wearable antennas, presented in this paper, is given in Table 5.  
This paper presents wideband active and tunable printed antennas with high efficiency for commercial and medical applications. The compact tunable antenna bandwidth is around 13% for a reflection coefficient lower than \(-9.5\) dB. The tunable antennas gain is around 2 dBi. A voltage-controlled diode is used to tune the wearable antenna resonant frequency at different positions on the patient body.  
The author declares no conflict of interest.