Abstract-An overall Low-Temperature Co-fired Ceramics (LTCC) package solution for X-band T/R module has been presented in this paper. This tile type package contributes to a dramatic reduction in size and weight of the T/R module. Moreover, an obvious merit of ceramic housing is better consistency of Coefficient of Thermal Expansion (CTE), compared with the traditional combination of ceramic board and metal housing. The schematic diagram and 3-D structure of the T/R module have been presented and a novel vertical interconnection based on Ball Grid Array (BGA) has been proposed to connect vias in the lid and those in the stage of the main LTCC pan. The LTCC T/R module has been fabricated and measured. It is compact in size (20 × 20 × 2.6 mm 3 ) and has a weight of 3.5 g. The measured transmit output power is 33 ± 1 dBm in the frequency range from 8.8 GHz to 10.4 GHz, and the measured receive gain and Noise Figure are 29-30.5 dB and 2.6-2.8 dB, respectively.
Summary
Dimensional change of the graphite assemblies due to irradiation is a key factor in limiting the service lifespan of the reactor core in small modular molten salt reactors. The graphite assembly structure, determining the fast neutron flux distribution and temperature distribution, has a notable impact on its dimensional change and hence its lifespan. In this article, we put forward an innovative solid hexagonal prism assembly (HPA) surrounded by fuel salt to prolong the lifespan of the graphite assemblies and compare it with the traditional hexagonal round channel assembly (RCA) with fuel salt flowing through its central round channel. Under the single‐cell model, the calculation results prove that the neutron flux distribution and temperature distribution in the HPA are more uniform than those in the RCA. The HPA deforms more slowly than the RCA under the same operating conditions. The lifespan of the RCA, defined as when it expands back to its original size, is 7.5 years under the 100 MW/m3 power density of fuel salt, while the lifespan of the proposed HPA is 8.4 years. The HPAs also allow a further expansion in the radial direction due to its noncontact arrangement in the core. It will take 14.9 years for the HPA assemblies to contact each other, which displays a significant improvement in lifespan.
The high-speed permanent magnet(HSPM) machines are extensively concerned in industries due to simple structure, high power densityand high frequency. This paper introduces a kind of hybrid rotor with Halbach configuration and graphite composite sleeve. The hybrid cooling technology of stator water cooling and rotor fo rced air cooling is adopted to prevent the PM from demagnetization at high temperature. A HSPM machine with 1.12 MW, 18000 rpm fo r direct driving of compressors is designed based on the multi-physics coupled analysis such as electromagnetic / temperature / stress / fluid fields. The experimental measurements validate the correctness of some methods.
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