Research On Negative Resistance Enhancement Of 2DEG Terahertz Wave? Amplifier And Modulator

Due to unique characteristics of terahertz wave,terahertz technology is significant to the theoretical research and practical application,such as object image,broadband mobile communications,radio astronomy,environmental monitoring,and medical diagnostics.High electron mobility transistor(HEMT)is wildly used in high frequency applications.For a HEMT with a sub-micrometer gate length,its excited plasma waves are laying in the terahertz range.Resonant tunneling diode(RTD)is a commonly used two-port element in high frequency.It has negative differential resistance,and can counteract energy loss caused by resistance.HEMT and RTD is very suitable for the manufacture of terahertz devices.This thesis is based on the characteristics of HEMT and RTD.The RTD's negative differential resistance is used to counteract the losses caused by the plasma wave propagation in the channel,which may cause power gain.In this thesis,the working principles of plasma waves in high electron mobility transistors and resonant tunneling diodes are analyzed in detail.In this basis,amplifier and modulator designed in this thesis is based on III-V semiconductor.The structure of amplifier is RTD-gated HEMT,and the structure of modulator is ORTD-gated HEMT.In this thesis,we have simulated amplifier and modulator in ADS software.Numerical and analytical results show that(a)the amplifier can realise power gain >8dB in 710 GHz and >5dB in 2.175 THz,(b)the modulator can realise modulation depth >95% and bandwith >40GHz.The amplifier and modulator may have a potential application in terahertz detection,communication and other fields.