Abstract Let T be a Wakamatsu tilting module. A module M is called （n, T）-copure injective （resp. （n, T）-copure flat） if εT^1（N, M） = 0 （resp. Г1^T（N, M） = 0） for any module N with T-injective dimension ...Abstract Let T be a Wakamatsu tilting module. A module M is called （n, T）-copure injective （resp. （n, T）-copure flat） if εT^1（N, M） = 0 （resp. Г1^T（N, M） = 0） for any module N with T-injective dimension at most n （see Definition 2.2）. In this paper, it is shown that M is （n, T）-copure injective if and only if M is the kernel of an In（T）-precover f ： A → B with A ∈ ProdT. Also, some results on Prod T-syzygies are presented. For instance, it is shown that every nth Prod T-syzygy of every module, generated by T, is （n, T）-copure injective.展开更多
In this paper,we have proposed a novel structure of Ka-band based phased array antenna with calibration function.In the design of Kaband antenna,the active phased array system is adopted and the antenna would work in ...In this paper,we have proposed a novel structure of Ka-band based phased array antenna with calibration function.In the design of Kaband antenna,the active phased array system is adopted and the antenna would work in the dual polarization separation mode.We have given out the schematic diagram for the proposed Ka-band antenna,where the Kaband antenna is in the form of waveguide slot array antenna,with 96 units in azimuth and 1 unit in distance.Each group of units is driven by a singlechannel Transmitter/Receiver(T/R)component,and the whole array contains 192 T/R components in total.The size of the T/R component is 55mm(length)×50mm(width)×5.8mm(height),3 Sub-micro Sub-Miniature Push-on(SSMP)blind sockets and a 21-core low-frequency socket are designed on the two sides of the T/R component.In order to meet the technical specifications of phased array antenna,the Ka-band transceiver component is designed based on Low Temperatrue Co-fired Ceramic(LTCC)technology to achieve miniaturization and lightweight.In our approach,the feed network includes two parts:transceiver network and calibration network.The transceiver network consists of 241:8 time-delay power dividers,12 two-way power dividers and 2 six-way time-delay power dividers.The power supply required by theKaband antenna unit is provided to each active component by the power module after Ka band wavelet control distribution.Simulation and measurement results are given in the form of standing wave and scanning capability.展开更多
This paper proposed an X-band 6-bit passive phase shifter （PS） designed in 0.18 μm silicon-on-insulator （SOI） CMOS technology, which solves the key problem of high integration degree, low power, and a small size ...This paper proposed an X-band 6-bit passive phase shifter （PS） designed in 0.18 μm silicon-on-insulator （SOI） CMOS technology, which solves the key problem of high integration degree, low power, and a small size T/R module. The switched-topology is employed to achieve broadband and fiat phase shift. The ESD circuit and driver are also integrated in the PS. It covers the frequency band from 7.5 to 10.5 GHz with an EMS phase error less than 7.5%. The input and output VSWRs are less than 2 and the insertion loss （IL） is between 8-14 dB across the 7.5 to 10.5 GHz, with a maximum IL difference of 4 dB. The input 1 dB compression point （IP1dB） is 20 dBm.展开更多
文摘Abstract Let T be a Wakamatsu tilting module. A module M is called （n, T）-copure injective （resp. （n, T）-copure flat） if εT^1（N, M） = 0 （resp. Г1^T（N, M） = 0） for any module N with T-injective dimension at most n （see Definition 2.2）. In this paper, it is shown that M is （n, T）-copure injective if and only if M is the kernel of an In（T）-precover f ： A → B with A ∈ ProdT. Also, some results on Prod T-syzygies are presented. For instance, it is shown that every nth Prod T-syzygy of every module, generated by T, is （n, T）-copure injective.
文摘In this paper,we have proposed a novel structure of Ka-band based phased array antenna with calibration function.In the design of Kaband antenna,the active phased array system is adopted and the antenna would work in the dual polarization separation mode.We have given out the schematic diagram for the proposed Ka-band antenna,where the Kaband antenna is in the form of waveguide slot array antenna,with 96 units in azimuth and 1 unit in distance.Each group of units is driven by a singlechannel Transmitter/Receiver(T/R)component,and the whole array contains 192 T/R components in total.The size of the T/R component is 55mm(length)×50mm(width)×5.8mm(height),3 Sub-micro Sub-Miniature Push-on(SSMP)blind sockets and a 21-core low-frequency socket are designed on the two sides of the T/R component.In order to meet the technical specifications of phased array antenna,the Ka-band transceiver component is designed based on Low Temperatrue Co-fired Ceramic(LTCC)technology to achieve miniaturization and lightweight.In our approach,the feed network includes two parts:transceiver network and calibration network.The transceiver network consists of 241:8 time-delay power dividers,12 two-way power dividers and 2 six-way time-delay power dividers.The power supply required by theKaband antenna unit is provided to each active component by the power module after Ka band wavelet control distribution.Simulation and measurement results are given in the form of standing wave and scanning capability.
文摘This paper proposed an X-band 6-bit passive phase shifter （PS） designed in 0.18 μm silicon-on-insulator （SOI） CMOS technology, which solves the key problem of high integration degree, low power, and a small size T/R module. The switched-topology is employed to achieve broadband and fiat phase shift. The ESD circuit and driver are also integrated in the PS. It covers the frequency band from 7.5 to 10.5 GHz with an EMS phase error less than 7.5%. The input and output VSWRs are less than 2 and the insertion loss （IL） is between 8-14 dB across the 7.5 to 10.5 GHz, with a maximum IL difference of 4 dB. The input 1 dB compression point （IP1dB） is 20 dBm.
