FMCW (frequency-modulated continuous wave radar) modulations have been popularly implemented in the automotive radar applications. This document demonstrates system requirement for a new FMCW modulation - fast chirp modulation. It largely improves the range resolution compare to general automotive FMCW Radar system. A practical RF-front end system is also presented at the end of the paper.

This paper presents a 45 degree linearly polarized microstrip comb-line antenna array for the 76.5 GHz automotive radar system. The 13-element array is implemented on Rogers RO3003 substrate with a size of 20 × 2 mm 2 . The measured gain of the antenna is 11.4 dBi and the sidelobe level is below −16.5 dB at 76.5 GHz.

This paper presents the design of a directional folded dipole antenna integrated in an embedded wafer level ball grid array (eWLB) package, the comparison of different antenna designs and the influence of the silicon die and neighboring antennas within the package to the radiation behavior. The co-integration of the antenna and the silicon-based monolithic microwave integrated circuit (MMIC) in a system in package (SiP) approach is a convenient solution to suppress lossy radio frequency (RF) transitions and to simplify the design and the manufacturing of radio frontends significantly. The proposed SiP is focused on 77-GHz automotive radar applications. The MMIC contains the 77-GHz signal source and a transceiver with amplifier and mixer. The gain of different antennas in different constellations within the package is shown.

This paper presents an antenna-in-package (AiP) solution with embedded wafer Level ball grid array (eWLB) packaging technology. The primary antenna is realized in the redistribution layer of the eWLB package. It is composed of two patches driven by differential signals and supports seamless connection with differential output monolithic microwave integrated circuits in a compact package. A dielectric rod lens was designed to optimize the radiation performance of the whole package. The final lens has the dimensions 10 mm × 10 mm × 10.5 mm. Our measurements show that the whole package (chip+AiP) including the lens reaches 16-dBm effective isotropic radiated power for the frequency range from 71.4 to 81.7 GHz. The radiation beam is relatively symmetric for both the E- and H-plane. The proposed AiP solution has great potential for millimeter-wave applications.

A microstrip half-grid array antenna (HGA) based on low temperature co-fired ceramic (LTCC) technology is presented in this paper. The antenna is designed for the 77-81 GHz radar frequency band and uses a high permittivity material (εr = 7.3). The traditional single-grid array antenna (SGA) uses two radiating elements in the H-plane. For applications using digital beam forming, the focusing of an SGA in the scanning plane (H-plane) limits the field of view (FoV) of the radar system and the width of the SGA enlarges the minimal spacing between the adjacent channels. To overcome this, an array antenna using only half of the grid as radiating element was designed. As feeding network, a laminated waveguide with a vertically arranged power divider was adopted. For comparison, both an SGA and an HGA were fabricated. The measured results show: using an HGA, an HPBW increment in the H-plane can be achieved and their beam patterns in the E-plane remain similar. This compact LTCC antenna is suitable for radar application with a large FoV requirement.

This paper studies the influence of the feed points on behavior of differential feed microstrip patch antennas. When the feed points are shifted from the center of the patch to the edge, higher order modes occur, for instance, TM 11 . As a result, the imaginary part of the differential antenna impedance shifts to higher values. The electrical separation condition (ψ) of the differential feed antenna is smaller for a center feed than that for an edge feed. Several antenna prototypes with different feed points were fabricated and measured. The measurements verify our analysis.

This paper presents an antenna in package (AiP) solution with embedded wafer level ball grid array (eWLB) packaging technology. The antenna implements superstrate structure configuration. A cavity in the PCB is introduced below the antenna area is introduced to increase the distance between antenna and ground on the PCB. This extends the relative bandwidth of the AiP by up to 36% for 10 dB return loss. Further, a hemisphere dielectric lens was also designed to improve the radiation performance of the AiP. Measurements show that the dielectric lens optimizes the radiation pattern of the AiP and increases the TX equivalent isotropic radiated power (EIRP) of the package from 9.0 dBm to 13.5 dBm at 76 GHz. This concept is suitable for a wide area of millimeter-wave front-end applications. The 3-dB beamwidths in the E- and H-planes of the package with lens were measured to be 38° and 53° respectively.

This paper presents a novel antenna in package solution with superstrate structure at 77 GHz for automotive radar applications. Two edge-coupled patches are driven by a differential signal which supports seamless integration with differential output MMICs in a single package. The antenna has a wide bandwidth (17 GHz) and stable gain. The antenna prototypes are fabricated using Embedded Wafer Level Ball Grid Array (eWLB) packaging technology. The measurement results show that the EIRP of the package (chip + antenna) reaches 11 dBm from 75 GHz to 80 GHz. This concept is suitable for a wide area of millimeter-wave front-end applications.

This letter presents an analysis of the impedances of differential feed microstrip rectangular patch antennas. It is shown that the impedance of a differential feed antenna exhibits cosine squared behavior over the feed distance. We present improved expressions for calculating the impedance match feed positions of a differential feed rectangular microstrip patch antenna with given dimensions, on the base of which we designed two antenna prototypes. Both simulation and measurement results match our theoretical prediction.

In this letter, a novel transition between a rectangular waveguide and coupled microstrip lines is presented. A differential microstrip patch antenna (DMPA) inside the waveguide acts as a radiation element. The antenna is composed of the main patch, the short-end parasitic patch, and the matching network. By implementing the short-end parasitic patch, the bandwidth of differential mode signals is greatly increased, while transmission of common mode signals is strongly suppressed. Back-to-back arrangements of such a transition were fabricated and measured. The results show that the 10 dB return loss bandwidth reaches 14.5 GHz, and the insertion loss at the center frequency (96 GHz) is 0.5 dB. Such a transition is suitable for numerous millimeter-wave applications.

This paper presents a multi-channel frequency-modulated continuous-wave (FMCW) radar sensor operating in the frequency range from 91 to 97 GHz. The millimeter-wave radar sensor utilizes an SiGe chipset comprising a single signal-generation chip and multiple monostatic transceiver (TRX) chips, which are based on a 200-GHz f(T) HBT technology. The front end is built on an RF soft substrate in chip-on-board technology and employs a nonuniformly distributed antenna array to improve the angular resolution. The synthesis of ten virtual antennas achieved by a multiple-input multiple-output technique allows the virtual array aperture to be maximized. The fundamental-wave voltage-controlled oscillator achieves a single-sideband phase noise of -88 dBc/Hz at 1-MHz offset frequency. The TX provides a saturated output power of 6.5 dBm, and the mixer within the TRX achieves a gain and a double sideband noise figure of 11.5 and 12 dB, respectively. Possible applications include radar sensing for range and angle detection, material characterization, and imaging.

In this paper an integrated wide-band transition from a differential micro-strip line to a rectangular WR-15 waveguide is presented. The transition makes use of a cavity that is entirely integrated into the multilayer printed circuit board (PCB), which offers three layers (RF signal layer, ground plane and DC signal layer) for signal routing. The transition including the 18 mm long micro-strip feed lines provides a bandwidth of 20 GHz from 50 GHz to 70 GHz and an insertion loss of less than 2.3 dB. This makes the transition perfectly suited for differential wide-band transceivers operating in the 60 GHz band.

A differential microstrip antenna array design for millimeter-wave applications is presented. The antenna is fed by coupled microstrip lines, which facilitates the integration of antennas and differential circuits in RF-front systems. In this work, such an antenna array was designed for an autonomous cruise control application at 77 GHz. The antenna array has a bandwidth of 2 GHz at −10 dB return loss. The radiation patterns of co-polarization are stable over the bandwidth due to the center-fed structure. The 3 dB beam widths are 28 degrees and 78 degrees in the E-plane and the H-plane, respectively, and cross-polarization is very low. The measurement results are in good agreement with the simulation results.

This paper presents a practical method to extract mixed-mode S-parameters of a micro-strip-to-waveguide transition that is fed by a differential micro-strip line. The measurements, however, can be carried out easily by utilizing a standard two-port vector network analyzer and using three different waveguide standards from a commercial waveguide calibration kit (short, offset short and termination). With this method a wide-band V-band transition from 50 GHz to 75 GHz was characterized.

This paper presents a practical method for extracting the S-parameters of a transition from a coupled microstrip line to a rectangular waveguide. By utilizing three standards (load, reflect, delayed reflect) for the waveguide port, the S-parameters (in both differential and common modes) of the transition can be calculated. A wide-band transition was tested to validate the calculation, and the results were in good agreement with expectations. This method is generic in the sense that it is suitable for other kinds of transitions, for instance, coplanar waveguide to waveguide, or coaxial line to waveguide, etc.

A novel 77-GHz directional folded dipole antenna integrated in an embedded wafer level ball grid array (eWLB) package is presented. For the characterization of the antenna a frequency multiplier is embedded, which scales the 4.25-GHz input signal up to 76.5 GHz and allows the use of a commercial signal source. The antenna structure is manufactured at the metallic layer, in the fan-out area of the package, and directly connected to the monolithic integrated frequency multiplier. The gain of the antenna is about 7 dBi, measured over a large bandwidth of about 8 GHz. The combination of the frequency multiplier with the on-package antenna is a promising approach to future radar modules in a single eWLB package for automotive radar applications. Such a module avoids 77-GHz transitions to the PCB and hence simplifies the design and manufacturing of the radar sensor significantly.

This paper presents a millimeter-wave transition from a Differential Microstrip Line (DMSL) to a rectangular waveguide. The key component of the transition is a Differential Microstrip Antenna (DMSA) - either a single patch DMSA or a gap-coupled patch DMSA. The gap-coupled patch increases significantly the bandwidth of the transition. Prototypes of both transitions were designed and manufactured, subsequent measurement results are in close agreement with the simulation results. This type of transition provides compact size and simple fabrication. It can be employed in a number of millimeter-wave applications.

A novel transition from rectangular waveguide to differential microstrip lines is illustrated in this paper. It transfers the dominant TE10 mode signal in a rectangular waveguide to a differential mode signal in the coupled microstrip lines. The common mode signal in the coupled microstrip lines is highly rejected. The transition was designed at 75 GHz, which is the center frequency of E band and simulated by a 3D EM simulator. It has a wide bandwidth of 19 GHz for -15 dB return loss of the waveguide port. Several prototypes of the transitions were fabricated and measured. The measurement results agree very well with the simulation. The compact size and the simple fabrication enable the transition to be employed in a number of millimeter-wave applications.

A novel differential microstrip patch antenna (DMPA) is designed for autonomous cruise control radar systems at 79 GHz. Distinct from conventional single-ended patch antennas, the DMPA uses a pair of coupled lines as feeding line. It eliminates the need of a balun in the RF frontend and supports the realization of more compact radar frontend. First, a single DMPA is designed. The impedance bandwidth reaches 4.7 GHz and the gain at 79 GHz is 6.2 dBi. Simulations show that the length of the patch determines the resonance frequency and the gap between the feed points affects the patch impedance. Furthermore, a four-element series-fed array is presented with 4.6 GHz bandwidth and 12.8 dBi gain. Both the single DMPA and the four-element DMPA array were fabricated and measured. Measurement results show good agreement with simulation results.