Fig. 1. Photo of the time-division multiplexing RF front end modules

Fig. 2. Diagram of the constituent parts of the RF front end

Fig. 3. Diagram of injection experiments on base station RF front end

Fig. 4. Waveform of the downlink signal

Fig. 5. Spectrum of the downlink signal

Fig. 6. Waveforms of the injected pulse and the reflected pulse under 200 mW

Fig. 7. Waveforms of the injected pulse and the reflected pulse under 20 W

Fig. 8. Reflected pulse waveform located in the downlink micro pulses

Fig. 9. Waveforms of the reflected pulses with different frequencies but same injection power

Fig. 10. Reflected waveforms of injection into filter merely

Fig. 11. Injected and reflected waveforms without filter