一种新型的在线式微波功率传感器

提出了一种基于MEMS技术的在线式微波功率传感器结构,并对该结构进行了理论分析、设计、制作和测量.该结构通过测量由MEMS膜耦合出的一小部分微波功率实现功率的测量.该结构制作工艺与GaAs MMIC工艺完全兼容.测量结果显示,在12GHz频率以内,微波功率传感器的反射系数小于-15dB,插入损耗小于2dB,在10GHz中心频率下的灵敏度为10 4μV/mW.     

一种开路短截线结构的耦合式微波功率传感器

提出了一种基于MEMS技术的在线式微波功率传感器结构,并对该结构进行了理论分析、设计、制作和测量。该微波功率传感器通过加入阻抗匹配和开路短截线结构实现低损耗和宽频带的在线测量。该结构制作工艺与GaAs MMIC工艺完全兼容。测量结果显示,在8GHz～12GHz频率范围内,微波功率传感器的反射系数小于-18dB,插入损耗优于0.45dB,在10GHz中心频率下的灵敏度为12.0μV/mW。     

一种具有工作状态转换开关结构的微机械在线式微波功率传感器

提出了一种具有工作和不工作两种状态的8GHz-12GHz宽带在线式微波功率传感器结构,该功率传感器通过测量由MEMS膜从共面波导线耦合出的一小部分微波功率实现功率的测量。为了降低功率传感器在不工作状态的微波损耗,提出了一种能够实现两种工作状态的新型的状态转换开关结构。该结构制作工艺与GaAs MMIC工艺完全兼容。测量结果显示,在10GHz中心频率处,该结构功率传感器在不工作状态下的插入损耗为0.18dB,而在工作状态下的插入损耗为0.24dB,这意味着在不工作状态下没有微波功率被耦合出来。     

双通道MEMS微波功率传感器的悬臂梁设计

为实现热电式MEMS微波功率传感器与电容式MEMS微波功率传感器的兼容,得到一种性能优良的双通道MEMS微波功率传感器,需要对MEMS悬臂梁的匹配特性进行分析与设计。根据MEMS悬臂梁的一维集中参数模型,分析了MEMS悬臂梁的吸合电压,研究了MEMS悬臂梁的位移与电容的变化关系以及MEMS悬臂梁的谐振频率,得到了MEMS悬臂梁的匹配特性与MEMS悬臂梁高度的变化关系。实验结果表明,当MEMS悬臂梁的高度设计为10 μm时,MEMS悬臂梁的谐振频率为16.13 kHz,在8～12 GHz频率范围内,回波损耗均小于－19 dB。     

热电式MEMS微波功率传感器的封装研究

为了研究热电式MEMS微波功率传感器封装后的性能,提出了一种COB技术的封装方案。首先,采用有限元仿真软件HFSS仿真封装前后的微波特性;然后,基于GaAs MMIC技术对热电式MEMS微波功率传感器进行制备,并对制备好的芯片进行封装。最后,对封装前后传感器的微波特性及输出特性进行测试。实验结果表明,在8～12 GHz频率范围内,封装后回波损耗小于-10.50 dB,封装前的灵敏度为0.16 mV/mW@10 GHz,封装后的灵敏度为0.18 mV/mW@10 GHz。封装后的热电式微波功率传感器输出电压与输入功率仍有良好的线性度。该项研究对热电式MEMS微波功率传感器封装的研究具有一定的参考价值和指导意义。     

面向5G的MEMS跷跷板结构功率传感器

为了解决5G功率传感器灵敏度不高的问题,创新性地提出一种可面向5G应用的MEMS跷跷板结构功率传感器。S参数测试结果表明,在1 GHz-10 GHz的频段内传感器的回波损耗小于-12.5 dB,插入损耗小于1.5 dB。功率响应测试表明,内部电容的灵敏度接近69.2aF/mW@1GHz、71.5aF/mW@5GHz和66.3aF/mW@10GHz,外部电容的灵敏度约为35.2aF/mW@1GHz、33.0aF/mW@5GHz和27.6aF/mW@10GHz,表明该跷跷板结构设计提高了传感器的灵敏度。     

毫米波10W空间功率合成放大器研制

提出了一种结构新颖的2×2空间功率合成结构.该结构在30~36GHz范围内,回波损耗优于10dB,插入损耗小于1dB.以此结构为基础再利用4块GaAs MMIC单片制作出了一个新型的功率合成器.该功率合成器在31~34GHz的频率范围内,在±0.64dB的增益波动下能得到大于10W的输出功率,并且在31GHz时具有最大的饱和输出功率13.8W,在带内的平均合成效率大于80%.     

一种DC～5GHz串联微波开关的温度特性和功率处理能力的测试与分析

描述了一种串联微波MEMS开关的设计、制造过程,它制作在玻璃衬底上,采用金铂触点,在DC～5GHz,插损小0.6dB,隔离度大于30dB,开关时间小于30μs.对这种微波开关的温度特性和功率处理能力进行了测试,在DC～4GHz,85℃下的插损增加了0.2dB,-55℃下的插损增加了0.4dB,而隔离度基本保持不变.在开关中流过的连续波功率从10dBm上升到35.1dBm,开关的插损下降了0.1～0.6dB,并且在35.1dBm(3.24W)下开关还能工作.和所报道的并联开关最大处理功率(420mW)相比,该结果说明串联开关具有较大的功率处理能力.     

S波段低噪声放大器设计

首先分析了低噪声放大电路的稳定性,功率增益及噪声系数的影响因素及改进方法;然后设计了一个中心频率为2.45 GHz,工作带宽为100MHz的S波段低噪声放大器.仿真结果表明,该放大器的噪声系数小于1 dB,功率增益大于28 dB,增益平坦度小于1 dB,输入/输出驻波比小于2:1.通过传统的电路板制作工艺实际制作了放大器电路,测试结果和仿真结果较一致.     

T形电极晶体管

叙述了一种制作双极型晶体管的T形电极结构自对准工艺。利用该工艺已研制成微波T形电极晶体管(TSET)。最高振荡频率为10GHz,截止频率为6GHz;在3.2GHz下,输出功率1.1W,功率增益6dB。     

A capacitive membrane MEMS microwave power sensor in the X-band based on GaAs MMIC technology

This paper presents the modeling, fabrication, and measurement of a capacitive membrane MEMS microwave power sensor. The sensor measures microwave power coupled from coplanar waveguide (CPW) transmission lines by a MEMS membrane and then converts it into a DC voltage output by using thermopiles. Since the fabrication process is fully compatible with the GaAs monolithic microwave integrated circuit (MMIC) process, this sensor could be conveniently embedded into MMIC. From the measured DC voltage output and S-parameters, the average sensitivity in the X-band is 225.43 μV/mW, while the reflection loss is below-14 dB. The MEMS microwave power sensor has good linearity with a voltage standing wave ration of less than 1.513 in the whole X-band. In addition, the measurements using amplitude modulation signals prove that the modulation index directly influences the output DC voltage.     

Sensitivity of MEMS microwave power sensor with the length of thermopile based on Fourier equivalent model

A Fourier equivalent model is introduced to research the thermal transfer behavior of a terminating-type MEMS microwave power sensor.The fabrication of this MEMS microwave power sensor is compatible with the GaAs MMIC process.Based on the Fourier equivalent model,the relationship between the sensitivity of a MEMS microwave power sensor and the length of thermopile is studied in particular.The power sensor is measured with an input power from 1 to 100 mW at 10 GHz,and the measurement results show that the power sensor has good input match characteristics and high linearity.The sensitivity calculated from a Fourier equivalent model is about 0.12,0.20 and 0.29 mV/mW with the length at 40,70 and 100μm,respectively,while the sensitivity of the measurement results is about 0.10,0.22 and 0.30 mV/mW,respectively,and the differences are below 0.02 mV/mW. The sensitivity expression based on the Fourier equivalent model is verified by the measurement results.     

Design and fabrication of a terminating type MEMS microwave power sensor

A terminating type MEMS microwave power sensor based on the Seebeck effect and compatible with the GaAs MMIC process is presented.An electrothermal model is introduced to simulate the heat transfer behavior and temperature distribution.The sensor measured the microwave power from-20 to 20 dBm up to 20 GHz.The sensitivity of the sensor is 0.27 mV/mW at 20 GHz.and the input retum loss is less than-26 dB over the entire experiment frequency range.In order to improve the sensitivity,four different types of coplanar waveguide(CPW) were designed and the sensitivity Was significantly increased by about a factor of 2.     

A micromachined inline type microwave power sensor with working state transfer switches

A wideband 8-12 GHz inline type microwave power sensor,which has both working and non-working states,is presented.The power sensor measures the microwave power coupled from a CPW line by a MEMS membrane.In order to reduce microwave losses during the non-working state,a new structure of working state transfer switches is proposed to realize the two working states.The fabrication of the power sensor with two working states is compatible with the GaAs MMIC(monolithic microwave integrated circuit) process.The experimental results show that the power sensor has an insertion loss of 0.18 dB during the non-working state and 0.24 dB during the working state at a frequency of 10 GHz.This means that no microwave power has been coupled from the CPW line during the non-working state.     

一种基于GaAs MMIC技术的X波段电容式膜桥MEMS微波功率传感器

This paper presents the modeling, fabrication, and measurement of a capacitive membrane MEMS microwave power sensor. The sensor measures microwave power coupled from coplanar waveguide （CPW） transmission lines by a MEMS membrane and then converts it into a DC voltage output by using thermopiles. Since the fabrication process is fully compatible with the GaAs monolithic microwave integrated circuit （MMIC） process, this sensor could be conveniently embedded into MMIC. From the measured DC voltage output and S-parameters, the average sensitivity in the X-band is 225.43μV/mW, while the reflection loss is below -14 dB. The MEMS microwave power sensor has good linearity with a voltage standing wave ration of less than 1.513 in the whole X-band. In addition, the measurements using amplitude modulation signals prove that the modulation index directly influences the output DC voltage.     

Low-voltage small-size double-arm MEMS actuator

The fabrication and characterisation of a double-arm cantilever-type metallic DC-contact MEMS actuator with low pull-down voltage are reported. Bi-layer TiW cantilevers with an internal stress gradient were fabricated using a microwave-compatible fabrication process. Owing to its small size, cantilever length (L = 5-50 mum) and width (W = 2-40 mum), i.e. ~10-100 times smaller in lateral dimensions than a standard MEMS actuator, this actuator showed actuation voltages lower than 10 V. RP measurements of the 10 mum-wide actuators yielded an average insertion loss less than 1 dB and isolation higher than 40 dB up to 25 GHz. The developed actuator is well suited for integration in reconfigurable microwave circuits and systems such as reconfigurable antennas and arrays.     

Microwave frequency detector at X-band using GaAs MMIC technology

The design,fabrication,and experimental results of an MEMS microwave frequency detector are presented for the first time.The structure consists of a microwave power divider,two CPW transmission lines,a microwave power combiner,an MEMS capacitive power sensor and a thermopile.The detector has been designed and fabricated on GaAs substrate using the MMIC process at the X-band successfully.The MEMS capacitive power sensor is used for detecting the high power signal,while the thermopile is used for detecting the low power signal.Signals of 17 and 10 dBm are measured over the X-band.The sensitivity is 0.56 MHz/fF under 17 dBm by the capacitive power sensor,and 6.67 MHz//μV under 10 dBm by the thermopile.respectively.The validity of the presented design has been confirmed by the experiment.