Isolators on antennas, the typical non-reciprocal devices, are used to protect high-power wireless transmitters from signal reflections. Currently, the widely used isolators are based on ferrite and other magnetic materials, which can’t meet the requirements of future communication technology for miniaturization as well as the compatibility with integrated circuit processes. This work introduces a Parity-Time (PT) symmetric LCR circuit to realize an integrated isolator. A pair of LCR resonators with gain and loss respectively are coupled by a varied capacitor to achieve tunable frequency. Floquet modulation is introduced to the loss resonator to generate multiple resonant modes that can be filtered in forward transmission while excited in backward transmission. The proposed isolator based on modulated PT-symmetric resonators is implemented on a printed circuit board in this work, the isolator designed achieves an insertion loss of −5.26dB with the isolation of 24.54dB at the center frequency of 12MHz. The non-reciprocal ratio is achieved as high as 29.8dB, which is much higher than the typical static counterpart. Besides, the nonreciprocal ratio still remains 25dB even with a 10% asymmetric design of the system, which breaks the limitations of PT-symmetric requirements. This work provides a potential solution for the future minimized isolators and asymmetric fabrication of PT-symmetric circuits.

A traditional LC-type passive wireless sensor has been used for the measurement in sealed environments. Due to the limitation of its operation principle, this method was only suitable for a single parameter monitoring. For most applications, it is desirable for multi-parameters to be monitored. In order to keep the chip area of the sensor as small as possible, multi-level inductors may be coaxially stacked. However, the transmitting signals affect each other due to strong mutual coupling between the stacked inductors. This paper presents a novel inductor structure by using a specific winding to achieve the minimized mutual inductance. Using the partial inductance theory, the mutual inductance of two stacked inductors is analyzed. Simulations of the two stacked inductors coaxially aligned, with each connected in a variable capacitor, show that the mutual inductance between the two inductors can be greatly suppressed. This phenomenon has also been verified through multi-layer PCB inductors. And capacitive temperature and pressure sensors were linked to the two stacked inductor to implement the simultaneous measurements of temperature and pressure. The measurement results indicate that the sensitivity of the temperature sensor is about 41.67 kHz/°C between -20°C to 100°C while the sensitivity of the pressure sensor is about -133.33 kHz/kPa between 50kPa to 110 kPa.

This paper presents an overview and development of 2-D micromachined thermal wind sensors. It first compares different types of wind sensors, then gives a brief introduction to three basic measurement principles of the thermal wind sensors: hot-wire or hot-film, calorimetric, and time of flight. In order to have a good understanding of development of the 2-D micromachined thermal wind sensors, they are first categorized into thermoresistive, thermoelectric, and thermoelectronic wind sensors based on their operations. Then, each category is further divided into different subcategories, according to their measuring principles and sensor configurations. In Section IV, different materials, fabrication processes, packaging techniques, and control modes of the 2-D micromachined thermal wind sensors are analyzed. This paper also evaluates the core technologies on how to improve the sensitivity, measurement range, and power consumption of the thermal wind sensors.

A novel three-dimensional (3-D) dynamic cellular automata (CA) model is presented for a photoresist-etching process simulation (photoresist-dissolution simulation and development simulation). In the 3-D dynamic CA model, the Moore neighborhood is adopted, and the boundary cells are only processed by using a boundary cell array, a corresponding linked list of pointers to the boundary cells, and a state flag to indicate the relations between the cells and the etching boundary. A time-compensation method is also introduced to speed up the photoresist-etching simulation. Therefore, the simulation speed is greatly increased compared with that of the static 3-D CA model, and the preferential etch in different directions reported in cell-removal models is significantly reduced. The 3-D dynamic CA model was successfully tested using some well-known etch-rate distribution test functions and has been shown to be stable, accurate, and fast. Exposure simulation, post-exposure bake simulation, and photoresist-etching simulation have been successfully integrated together to further study the effectiveness of the 3-D dynamic CA model. Simulation results show an agreement with available experimental results