CPW line and realized by LTCC process for smaller size. The size of the miniaturized antenna is about 8 ϫ 15 mm 2 . As a result, we obtained the stop band from 4.8 to 6.3 GHz. The proposed antennas are good candidates for UWB systems where stop band is needed.ABSTRACT: A 77-GHz six-port frequency modulated continuous wave collision avoidance radar sensor is proposed. Velocity and range are determined from the slope of the instantaneous phase of radar beat signals. Digital signal processing techniques are developed to overcome DC offset and amplitude imbalance problems. Figure 1 Block diagram of the six-port for the I/Q mixer 720

In this paper, a high dynamic range V‐band power detector designed in thin film Miniature Hybrid Microwave Integrated Circuit (MHMIC) process is presented and characterized. The commercially available HSCH‐9161 millimeter‐wave zero bias GaAs Schottky diode is selected to manufacture the proposed power detector circuit, along with a broadband rectangular WR12 waveguide to microstrip transition, and an optimized microstrip impedance matching network. The design and characterization steps are described in detail to provide a consistent methodology to design high‐performance power detectors, while taking into account the accuracy, nonlinearity, and limitation of the measurement devices. The fabricated power detector prototype exhibits good input impedance matching (bandwidth of 3.8 GHz), high operational stability over 58.5–62 GHz frequency range, excellent sensitivity (−48 dBm), and high detection responsivity (peak of 8250 mV/mW at 61.2 GHz).

A millimeter‐wave six‐port implementation using combined substrate‐integrated waveguide (SIW) and microstrip technologies, and low‐loss short transition between microstrip and SIW is presented. The six‐port is implemented using SIW hybrid couplers with continuous metalized grooves and Wilkinson power dividers. The proposed circuit is suitable for 77‐GHz radar sensor front ends. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2488–2493, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25538