| CPC G01S 7/032 (2013.01) [G01S 7/027 (2021.05); G01S 13/931 (2013.01); H01Q 1/3233 (2013.01)] | 11 Claims | 

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               1. A radar apparatus, comprising: 
            a circuit board including a board surface provided with an antenna module for transmitting an electromagnetic wave; 
                a housing accommodating the circuit board and including a facing wall facing the board surface; and 
                a heat transfer module transferring heat generated inside the housing to the housing, wherein 
                the facing wall includes: 
                a transmission portion transmitting therethrough the electromagnetic wave transmitted from the antenna module, the transmission portion having a first thickness corresponding to a wavelength of the electromagnetic wave transmitted from the antenna module; and 
                  an absorption portion having a second thickness different from the first a thickness of the transmission portion, the second thickness corresponding to an effective wavelength of the electromagnetic wave, and the absorption portion is configured to reabsorb a re-incident electromagnetic wave reflected from an object outside the housing which is re-incident on the housing, the absorption portion being made of a same material as the transmitting portion, and wherein 
                the absorption portion absorbs the electromagnetic wave by reverse-phase synthesis of: 
              a first electromagnetic wave resulting from reflection of the re-incident electromagnetic wave at a first surface of the absorption portion, and 
                  a second electromagnetic wave resulting from reflection of the re-incident electromagnetic wave at a second surface different from the first surface. 
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