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A novel die sorter based on mechanical gripper was developed for picking and placing diced terahertz Schottky barrier diodes (SBD). The designing and working principle of die sorter are based on flexible hinge and linear-actuator. Dimensions of dies gripped by the sorter can be as small as 100 µm * 50 µm* 15 µm without damage to its air-bridge. For flipping upside down dies, the rotation motion was obtained by rotating linear actuator about its shaft. It is demonstrated that the placement accuracy of the sorter can achieve less than 9.5 µm and 3.0 µm in x-y direction respectively.

A 30 GHz monolithically integrated frequency multiplier based on the planar GaN Schottky barrier diode are successfully fabricated. The impact of material parameters and anode dimension on the frequency multiplier are investigated. The use of the monolithic integrated approach significantly improves the performance of the GaN frequency multiplier. The frequency multiplier gains a more than 3 dBm output power with frequency range from 21.5 to 39.5 GHz. The maximum output power is 9.68 dBm at 28.5 GHz with efficiency up to 16.1%. At the central frequency of 30 GHz, the output power is 9.64 dBm with 15.0% efficiency.

The fabrication and characteristics of balanced metal-semiconductor-metal (MSM) two-dimensional electron gas (2DEG) varactors based on AlGaN/GaN high electron mobility transistor (HEMT) for terahertz circuits were presented. The cathodes were designed to be strip-gates with submicron length of $\sim 450$ nm and manufactured by using electron beam lithography (EBL). The anodes lengths are ranging from $\sim 450$ nm to $\sim 2 \mu$m to study the influence of anode size on DC and high frequency characteristics. The DC and high frequency measurements were carried out, current-voltage and capacitance-voltage characteristics were investigated. As increasing the size of anode size to 2 $\mu $ m, the cutoff frequency of the MSM varactors was increasing as well. By matching the equivalent circuit at zero bias voltage with anode size of 2 $\mu$ m, the series resistance (R 0 ) of $\sim$ 32.43 $\Omega$, and the capacitance (C 0 ) of $\sim$ 5.09 fF were abstracted respectively, and the cutoff frequency of $\sim$ 964.6 GHz and the figure of merit (FOM) of 4.07 THz were obtained.

The sphincter of Oddi is a valve that controls the biliopancreatic duct and plays an irreplaceable role in maintaining normal physiological functions of the biliopancreatic duct. However, sphincteroplasty and sphincterotomy may cause varying degrees of damage to the function of the sphincter of Oddi, which may further result in postoperative reflux of duodenal fluids and bacterial contamination in bile and increase the risks of recurrent common bile duct stones, reflux cholangitis, and even cholangiocarcinoma. Therefore, clinical physicians should protect the structure and function of the sphincter of Oddi. Based on our experience, under the premise that the extrahepatic bile duct can be preserved, patients with iatrogenic injury of the sphincter of Oddi can be treated with transduodenal sphincteroplasty to restore the structural integrity of the sphincter of Oddi and reduce biliopancreatic duct complications secondary to loss of function.

Attack graph can simulate the possible paths used by attackers to invade the network. By using the attack graph, the administrator can evaluate the security of the network and analyze and predict the behavior of the attacker. Although there are many research studies on attack graph, there is no systematic survey for the related analysis methods. This paper firstly introduces the basic concepts, generation methods, and computing tasks of the attack graph, and then, several kinds of analysis methods of attack graph, namely, graph-based method, Bayesian network-based method, Markov model-based method, cost optimization method, and uncertainty analysis method, are described in detail. Finally, comparative study of the methods and future work are provided. We believe that this work would help the research community to understand the attack graph analysis method systematically.

The design, fabrication and characteristics of planar metal-semiconductor-metal (MSM) two-dimensional electron gas (2DEG) varactors based on AlGaN/GaN high electron mobility transistor (HEMT) for terahertz multiplication are presented. The gate length of ~450nm and the gate distance of $1\mu\ \text{m}$ are processed by using electron beam lithography (EBL). The DC characteristic shows a very low current leakage of ~7.3 $\times 10^{-11}\quad \mathbf{A}/\mathbf{mm}$ , which is advantageous to the power consumption of terahertz multiplier. S-parameters are measured to obtain the high-frequency performance. The series resistance $(\mathbf{R})\mathbf{of}\sim 41.26\ \Omega$ , and the capacitance $(\text{C}_{0})$ of ~4.22fF are abstracted respectively by matching the equivalent circuit at zero bias voltage. The cutoff frequency is of $\sim 914.5$ GHz. The capacitance switching ration $(\mathbf{C}_{\max}/\mathbf{C}_{\min})$ is $\geqslant 2.4$ , and the figure of merit (FOM) is above 2.2 THz

GaN Schottky barrier diodes have great potential for high power, high temperature and high frequency applications. We describe in this paper the design, fabrication and measurement of the GaN planar SBD with the air-birdge technology and electroplating technology for reducing the parasitic parameters. The typical On-wafer DC current-voltage and small-signal S-parameter measurements were characterized at room temperature, respectively. The impact of anode shape and dimension were investigated. The GaN planar SBD with $3\times 4\mu\mathrm{m}^{2}$ anode area had a cut-off frequency of 360 GHz and a breakdown voltage of -10 V.

The air-bridge interconnection is an extremely effective structure for improving the device performance in MMICs, but its application is limited by the complexity in fabrication and high temperature process required for baking photoresist. In this paper, we present a low temperature $( process for the fabrication of air-bridge in microwave devices. By choosing two types of suitable photoresists and optimizing the hard baking time of the sacrificial photoresist, we obtain high structural strength arched structure air-bridges with the entire process carried out at low temperature and complexity reduced. We have successfully fabricated four-finger HEMT devices.