## 3 Experimental Results
### Conventional Cascaded Design of the Microwave Amplifier-Phase Shifter  
To design the conventional cascaded MA-PS, the microwave amplifier and the reflection-type phase shifter are designed individually by assuming port impedances of 50-to-50 \(\Omega\). Figure 10a depicts the PCB layout with the physical dimensions of the conventional reflection-type phase shifter by using the 3 dB branch-line hybrid [26]. The design goals of the conventional reflection-type phase shifter are to achieve a phase shift range of \(>\)180\({}^{\circ}\) and a phase deviation error of \(<\pm\)8\({}^{\circ}\) within a bandwidth of 200 MHz at \(f_{0}=2.45\) GHz. The circuit parameters of the conventional reflection-type phase shifter are given as \(Z_{A}=Z_{C}=35.36\)\(\Omega\); \(Z_{B}=Z_{D}=50\)\(\Omega\); \(Z_{r}=50\)\(\Omega\); \(\theta_{r}=45^{\circ}\); and \(C_{v}\) of varactor diode SMV1231, which provide capacitance ranging from 0.33 pF to 4.87 pF by varying the voltage from 0 V to 15 V. The values of \(Z_{r}\) and \(\theta_{r}\) are selected using the method described in Section 2.2. For practical realization, additional TLs with parameters of \((W_{1}\)\({}^{\prime}\)/\(L_{1}\)\({}^{\prime}\)) and \((W_{1}\)\({}^{\prime}\)/\(L_{3}\)\({}^{\prime}\)) are used as soldering pads. Additionally, to vary the capacitance of the varactor diode, a single \(V_{DC}\) feeding line \((W_{3}\)\({}^{\prime}\)/\(L_{2}\)\({}^{\prime}\)) with \(Z_{DC}=100\)\(\Omega\) and \(\theta=90^{\circ}\) is connected to the middle of the conventional reflection-type phase shifter vertical branch. These additional TLs affect the phase shift range and phase deviation error of conventional reflection-type phase shifter. Figure 10b illustrates the comparison of the phase shift range between the EM simulation and measurement results. The measured phase shift range is 188.97\({}^{\circ}\) with a maximum phase deviation error of \(\pm\)6\({}^{\circ}\) within the desired BW. Furthermore, a comparison of \(S\)-parameters between EM simulation and measurement results is shown in Figure 10c, where the maximum IL of 0.52 dB and minimum RL of 22 dB are obtained within an operation band ranging from 2.35 GHz to 2.55 GHz. Figure 9: Conventional microwave amplifier design: (**a**) structure, (**b**) PCB layout with physical dimensions, and (**c**) \(S\)-parameters. Circuit dimensions: \(W_{1}=2.38\); \(W_{2}=0.7\); \(W_{3}=3.4\); \(L_{1}=10\); \(L_{2}=11.82\); \(L_{3}=4.45\); \(L_{4}=11.9\); \(L_{5}=2\); \(L_{6}=4.7\); \(L_{7}=12\) [unit: millimeter] (CIMN: conventional input matching network; COMN: conventional output matching). Figure 11a depicts the circuit layout of the cascaded microwave amplifier-phase shifter, where the output port of the conventional reflection-type phase shifter is connected to the input port of the conventional microwave amplifier. As the space between the input port of conventional reflection-type phase shifter and conventional input matching network of conventional microwave amplifier is too small, the additional TL with physical parameters of (\({W_{1}}^{\prime}/{L_{1}}^{\prime\prime}\)) is used and bent by \(90^{\circ}\) for the input port connection. Figure 11b,c show the phase shift range and \(S\)-parameters comparison between the simulation and measurement results of the conventional reflection-type phase shifter cascaded with a conventional microwave amplifier at \(f_{0}\) of 2.45 GHz, respectively. Since the conventional reflection-type phase shifter contains IL, the cascading conventional reflection-type phase shifter with conventional microwave amplifier can degrade electrical performances such as gain and output power. In addition, if each of these circuits is not perfectly matched to 50 \(\Omega\), additional losses will occur due to an impedance mismatch. As a result, the measured maximum phase shift range is \(195.35^{\circ}\) at \(f_{0}\) and the maximum phase deviation error over BW of 200 MHz is \(\pm 6.14^{\circ}\), which is comparable to the simulation.