Pub Date : 2024-02-01DOI: 10.1088/1674-4527/ad24f6
Kai Wang, Liang Cao, Jun Ma, X. Duan, Hao Yan, Mao-zheng Chen, Yun-Wei Ning
The receiver is a signal receiving device placed at the focus of the telescope. In order to improve the observation efficiency, the concept of phased array receiver has been proposed in recent years, which places a small phased array at the focal plane of the reflector, and flexible pattern and beam scanning functions can be achieved through a beamforming network. If combined with the element multiplexing, all beams within the entire field of view can be observed simultaneously to achieve continuous sky coverage. This article focuses on the front-end array of phased array receiver at 0.7-1.8 GHz for QiTai Telescope, and designs a Vivaldi antenna array of PCB structure with dual line polarization. Each polarization antenna is designed to arrange in a rectangle manner by 11 × 10. Based on the simulation results of the focal field, 32, 18 and 8 elements were selected to form one beam at 0.7, 1.25 and 1.8 GHz. A analog beamforming network was constructed, and the measured gains of axial beam under uniform weighting were 19.32, 13.72 and 15.22 dBi. Combining the beam scanning method of reflector antenna, the pattern test of different position element sets required for PAF beam scanning was carried out under independent array. The pattern optimization at 1.25 GHz was carried out by weighting method of conjugate field matching. Compared with uniform weighting, the gain, sidelobe level, and main beam direction under conjugate field matching have been improved. Although the above test and simulation results are slightly different, which is related to the passive array and laboratory testing condition, the relevant work has accumulated experience in the development of front-end array for phased array receiver, and has good guiding significance for future performance verification after the array is installed on the telescope.
{"title":"Development of a Front End Array for Broadband Phased Array Receiver","authors":"Kai Wang, Liang Cao, Jun Ma, X. Duan, Hao Yan, Mao-zheng Chen, Yun-Wei Ning","doi":"10.1088/1674-4527/ad24f6","DOIUrl":"https://doi.org/10.1088/1674-4527/ad24f6","url":null,"abstract":"\u0000 The receiver is a signal receiving device placed at the focus of the telescope. In order to improve the observation efficiency, the concept of phased array receiver has been proposed in recent years, which places a small phased array at the focal plane of the reflector, and flexible pattern and beam scanning functions can be achieved through a beamforming network. If combined with the element multiplexing, all beams within the entire field of view can be observed simultaneously to achieve continuous sky coverage. This article focuses on the front-end array of phased array receiver at 0.7-1.8 GHz for QiTai Telescope, and designs a Vivaldi antenna array of PCB structure with dual line polarization. Each polarization antenna is designed to arrange in a rectangle manner by 11 × 10. Based on the simulation results of the focal field, 32, 18 and 8 elements were selected to form one beam at 0.7, 1.25 and 1.8 GHz. A analog beamforming network was constructed, and the measured gains of axial beam under uniform weighting were 19.32, 13.72 and 15.22 dBi. Combining the beam scanning method of reflector antenna, the pattern test of different position element sets required for PAF beam scanning was carried out under independent array. The pattern optimization at 1.25 GHz was carried out by weighting method of conjugate field matching. Compared with uniform weighting, the gain, sidelobe level, and main beam direction under conjugate field matching have been improved. Although the above test and simulation results are slightly different, which is related to the passive array and laboratory testing condition, the relevant work has accumulated experience in the development of front-end array for phased array receiver, and has good guiding significance for future performance verification after the array is installed on the telescope.","PeriodicalId":509923,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"336 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139876928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-15DOI: 10.1088/1674-4527/ad1ed2
Peixin Luo, Baolin Tan
Solar activities have a great impact on modern high-tech systems, such as human aerospace, satellite communication and navigation, deep space exploration, and related scientific research. Therefore, studying the long - term evolution trend of solar activity and accurately predicting the future solar cycles is highly anticipated. Through wavelet transform and empirical function fitting of the longest recorded data of the annual average relative sunspot number (ASN) series of 323 years to date, this work decisively verified the existence of the solar century cycles and confirmed that its length is about 104.0 years, and the magnitude has a slightly increasing trend on the time scale of several hundreds of years. Based on this long-term evolutionary trend, we predicted solar cycle 25 and 26 by using phase similar prediction methods. As for the solar cycle 25, its maximum ASN will be about 146.7 ± 33.40, obviously stronger than solar cycle 24. The peak year will occur approximately in 2024, and the cycle length is about 11 ± 1 years. As for the solar cycle 26, it will start around 2030, reach the maximum between 2035 and 2036, with maximum ASN of about 133.0 ± 3.200, and the cycle length is about 10 years.
{"title":"Long-term evolution of solar activity and prediction of the followingsolar cycles","authors":"Peixin Luo, Baolin Tan","doi":"10.1088/1674-4527/ad1ed2","DOIUrl":"https://doi.org/10.1088/1674-4527/ad1ed2","url":null,"abstract":"\u0000 Solar activities have a great impact on modern high-tech systems, such as human aerospace, satellite communication and navigation, deep space exploration, and related scientific research. Therefore, studying the long - term evolution trend of solar activity and accurately predicting the future solar cycles is highly anticipated. Through wavelet transform and empirical function fitting of the longest recorded data of the annual average relative sunspot number (ASN) series of 323 years to date, this work decisively verified the existence of the solar century cycles and confirmed that its length is about 104.0 years, and the magnitude has a slightly increasing trend on the time scale of several hundreds of years. Based on this long-term evolutionary trend, we predicted solar cycle 25 and 26 by using phase similar prediction methods. As for the solar cycle 25, its maximum ASN will be about 146.7 ± 33.40, obviously stronger than solar cycle 24. The peak year will occur approximately in 2024, and the cycle length is about 11 ± 1 years. As for the solar cycle 26, it will start around 2030, reach the maximum between 2035 and 2036, with maximum ASN of about 133.0 ± 3.200, and the cycle length is about 10 years.","PeriodicalId":509923,"journal":{"name":"Research in Astronomy and Astrophysics","volume":"7 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139529465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：