## 3 Experimental Results
### Results Comparison  
Figure 13 shows photographs of prototypes of a standalone microwave amplifier, a proposed co-design microwave amplifier with a reflection-type phase shifter input matching network, and a conventional reflection-type phase shifter cascaded with a conventional microwave amplifier. In this work, capacitors from Tekelec are used and are listed in Table 3. Meanwhile, the measured \(S\)-parameters of all fabricated prototypes are shown in Figure 14a, where the gains of the standalone conventional microwave amplifier, the conventional reflection-type phase shifter cascaded with conventional microwave amplifier, and the proposed co-design microwave amplifier-phase shifter are 14.13 dB, 13.28 dB, and 13.74 dB, respectively. As can be seen from these results, the proposed co-design microwave amplifier-phase shifter exhibits a higher gain across the entire frequency range than the conventional reflection-type phase shifter cascaded with a conventional microwave amplifier, highlighting its effectiveness in enhancing gain performance. For output power  
measurements, a continuous-wave signal is used. Figure 14b shows the measured output power and gain of all fabricated microwave amplifiers according to input power (\(P_{\text{in}}\)). By increasing \(P_{\text{in}}\) from \(-15\) dBm to \(15\) dBm, the output power reached its \(1\) dB compression point (\(P_{\text{1 dB}}\)). At \(f_{0}\), the measured output power at \(P_{\text{1 dB}}\) of the conventional microwave amplifier is \(25.72\) dBm. Similarly, the \(P_{\text{1 dB}}\) of conventional reflection-type phase shifter cascaded with the conventional microwave amplifier and the proposed co-design microwave amplifier-phase shifter are \(24.77\) dBm and \(25.26\) dBm, respectively. At \(P_{\text{1 dB}}\), the gains of the standalone conventional microwave amplifier, the conventional reflection-type phase shifter cascaded with the conventional microwave amplifier, and the proposed co-design microwave amplifier-phase shifter are \(13.11\) dB, \(12.25\) dB, and \(12.73\) dB, respectively. Even though the conventional microwave amplifier exhibits the highest gain, this circuit does not consider phase shift functionality. The phase shift range and phase deviation error performance comparison of the conventional reflection-type phase shifter cascaded with conventional microwave amplifier and the proposed co-design microwave amplifier phase shifter can be found in Table 4.  
Figure 13: Photograph of fabricated microwave amplifiers: (**a**) conventional microwave amplifier, (**b**) proposed co-design microwave amplifier with reflection-type phase shifter input matching network, and (**c**) conventional reflection-type phase shifter cascaded with conventional microwave amplifier (IMN: input matching network; CIMN: conventional IMN; COMN: conventional output matching network; RTPS: reflection-type phase shifter; CRTPS: conventional RTPS; CMA: conventional microwave amplifier). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Target** & **Part Number of Used Capacitors** & **Measured Capaciances at 2.45 GHz** \\ \hline \(C_{\text{mic}}=0.1\) pF & V)0603 DOR1 VXPAJ & \(C_{\text{mic},\text{mic},\text{mic}}=0.13\) pF \\ \hline \(C_{\text{phy}}=33\) pF & 0603 NBR2 AW251 & \(C_{\text{phy},\text{mic}}=32.92\) pF \\ \hline \(DC_{\text{exp}}=20\) pF & 0603 NBR6 AW251 & \(DC_{\text{exp},\text{mic}}=20.1\) pF \\ \hline \(C_{\text{s}}=4.87\) pF & 0603 NBR3 AW251 & \(C_{\text{s},\text{mic}}=4.9\) pF \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Parameters of capacitors used in Figures 10a, 11a and 12a. Table 4 summarizes the key performance metrics of the three fabricated prototypes. The proposed co-design circuit demonstrates superior gain and power compared to the conventional cascaded design.