In this paper, the aim is to develop a radio wave type laparoscope that can project an image of the blood vessel in real time. The proposed system consists of one transmitting antenna and four receiving antennas. The position of the blood vessel is detected by signal-processing the received radio wave to image data by the method of processing synthetic aperture. The diameter of the practical laparoscope is usually 10mm. In this study, however, a system with a 25mmdiameter (a 2.5-times scale model) is designed in order to facilitate of the measurement. In the analytical model, the transmitting antenna and four receiving antennas are located on the top of the fat. Two arrangements of the transmitting antenna are investigated using the simulated reflection and transmission coefficients. The differences between the transmission coefficients in the cases with and without the blood vessel are observed.