Fig. 1. Structure of millimeter wave security inspection imaging system. (a) Core components; (b) transmitting front-end module

Fig. 2. Transmission line models and performance curves of grounded coplanar waveguides and microstrip structures. (a) Three-dimensional simulation structure; (b) comparison of simulation results of S parameters

Fig. 3. Two-port equivalent circuit. (a) Bonding wires; (b) equivalent “T” type network with compensation of high-low impedance line

Fig. 4. Schematic and performance curves of transmission line before and after high-low impedance line compensation. (a) Before compensation; (b) after compensation; (c) comparison of simulation results of S parameters

Fig. 5. Switch chip evaluation board. (a) SP4T switch; (b) SPDT switch

Fig. 6. Simulation and measurement results of S parameters of different chips. (a) SPDT switch chip evaluation board; (b) SP4T switch chip evaluation board

Fig. 7. Layout and performance curves of 8-channel switch subcircuits. (a) Actual assembly photograph; (b) simulation results of S parameters under different channels

Fig. 8. Octave frequency multiplier structure and spectrum simulation curves. (a) Chain block diagram; (b) harmonic simulation results

Fig. 9. Schematic and performance curves of wideband bandpass filter. (a) 3D models and; (b) Simulation results of S parameters

Fig. 10. Test framework for transmitting front-end

Fig. 11. Measured results of transmitting front-end module. (a) Output power of each channel and isolation between channels; (b) harmonic rejection

Fig. 12. Schematic of imaging experiment and experimental results. (a) Schematic of imaging scene; (b) original image of active millimeter wave imaging