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Such conditions will result in the conventional radar range equation being unsuitable. Therefore, the near-field radar cross section (RCS) formula is given according to the numerical simulation on different targets. By modifying the parameters in the near field, including the gain of radar antennas and the RCS of targets, the generalized radar range equation is proposed. The THz radar working efficiency in the whole range and the simulation of the near-field RCS simulation model were employed to validate its effectiveness. Through comparison with the radar range equation, it can be concluded that the calculation results of the proposed equation are smaller in the near field, and the outcomes in the far field are identical. The proposed generalized radar range equation can be applied to the whole radiation area including the near field and the far field. Furthermore, more complicated real targets are calculated according to the generalized radar range equation and it can be extended from the submillimeter wave band to a much wider band range. Finally, the near-field radar theory is established, which shows its potential application to the radar cross section estimation in the extremely high frequency and fine design of THz radar systems.<\/jats:p>","DOI":"10.3390\/s22124608","type":"journal-article","created":{"date-parts":[[2022,6,19]],"date-time":"2022-06-19T21:19:26Z","timestamp":1655673566000},"page":"4608","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":19,"title":["Generalized Radar Range Equation Applied to the Whole Field Region"],"prefix":"10.3390","volume":"22","author":[{"given":"Luyin","family":"Xiao","sequence":"first","affiliation":[{"name":"School of Electronic and Information Engineering, Beihang University, Beijing 100191, China"},{"name":"Beijing Key Laboratory of Microwave Sensing and Security Applications, Beihang University, Beijing 100191, China"},{"name":"Shenzhen Institute of Beihang University, Shenzhen 518000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yongjun","family":"Xie","sequence":"additional","affiliation":[{"name":"School of Electronic and Information Engineering, Beihang University, Beijing 100191, China"},{"name":"Beijing Key Laboratory of Microwave Sensing and Security Applications, Beihang University, Beijing 100191, China"},{"name":"Shenzhen Institute of Beihang University, Shenzhen 518000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shida","family":"Gao","sequence":"additional","affiliation":[{"name":"School of Electronic and Information Engineering, Beihang University, Beijing 100191, China"},{"name":"Beijing Key Laboratory of Microwave Sensing and Security Applications, Beihang University, Beijing 100191, China"},{"name":"Shenzhen Institute of Beihang University, Shenzhen 518000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Junbao","family":"Li","sequence":"additional","affiliation":[{"name":"School of Electronics and Information Engineering, Harbin Institute of Technology, Harbin 150080, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9311-8045","authenticated-orcid":false,"given":"Peiyu","family":"Wu","sequence":"additional","affiliation":[{"name":"School of Electronic and Information Engineering, Beihang University, Beijing 100191, China"},{"name":"Beijing Key Laboratory of Microwave Sensing and Security Applications, Beihang University, Beijing 100191, China"},{"name":"Shenzhen Institute of Beihang University, Shenzhen 518000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,6,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"174","DOI":"10.1109\/TTHZ.2017.2787465","article-title":"Bistatic Synthetic Aperture Radar with Undersampling for Terahertz 2-D Near-Field Imaging","volume":"8","author":"Ding","year":"2018","journal-title":"IEEE Trans. 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