Skickas inom vardagar. Laddas ned direkt. The steady evolution of wireless communication technologies continues to pave the way for the implementation of innovative services and devices in modern vehicles. These include analog and digital audio broadcasting radio, satellite radio, GPS, cell phones, and short range communication devices. Such applications require the use multiple antennas operating in different frequency ranges. Automotive Antenna Design and Applications thoroughly examines traditional and new advanced automotive antennas, including the principles, designs, and techniques used to reduce antenna dimensions without significant degradation of communication quality.
The contents of this book are based on cutting-edge data collected from numerous technical papers, patents, and patent applications. It presents an overview of many commercially available automotive antennas and covers features that have become standard in automotive applications, such as printed-on car glass antennas, reduced-size helical antennas, multiband compact, printed-on dielectric and patch designs in a single package.
Includes simulation examples of antenna parameters that significantly speed up the design process using software packages such as FEKO, NEC, IE3D, and Genesys Highlighting the practical aspects of antenna design, the authors present passive and active designs and describe the entire design process, including antenna simulation, prototype sample fabrication, and laboratory test measurements.
The book also covers the production adjustments that can result from the demands of the real car environment. More recently, radar systems have been implemented in automobiles.
Automotive radar systems are known for use in helping drivers to park their cars, to follow traffic at a safe distance, and to detect driving obstacles. In such.
This round-trip delay, divided in half and then multiplied by the speed of the radiation, c, gives the distance between the radar system and the target object assuming the transmitting antenna and the receiving antenna are the same antenna or very close to each other. The antenna arrays may include a plurality of arrays arranged for particular performance characteristics. All antennas may have a desirable large frequency bandwidth with relatively flat antenna gain over a frequency range from 22 to In addition, measured sidelobe levels for the elevation patterns are below dB.
Design software accelerates antenna array development for automotive radar applications
Typical microstrip patch antenna arrays present a relatively low cost option, however, traditional patch antenna arrays have relatively narrow bandwidth, and suffer from signal leakage from the associated feeding network. One way to minimize feeding network losses and unwanted radiation from the feeding network is to use a four element sub-array.
With such a sub-array, a plurality of radiation patches are excited by a resonant patch positioned beneath the radiation patches. The bandwidth of the resulting sub-array antenna may be increased through this resonant coupling, while relatively higher antenna gain is achieved through the configuration of a plurality of patches having high radiation efficiency. To meet regulatory emissions requirements and to minimize the reception from the off-sight targets, such as the guardrails, the metal bridge frames, etc, however, automotive antennas must also have very low sidelobe radiation while maintaining desired high efficiency.
Consequently, a large array may be needed. In addition, for mid- and short-range radar applications, both high and low gain antennas may be required. To eliminate issues associated with target angle detection ambiguity, two columns of radiation arrays may be provided very close to each other i. To build a large array from such four element sub-arrays without sacrificing bandwidth and high antenna gain is a challenge due to the presence of field interference from the feeding network and from the feeding patches disposed between the radiation layer and the antenna ground.
Another challenge is that the top four patches of a sub-array may be limited in the amount of space they are allowed to occupy. Patch antennas may be desirable because they can be fabricated in a compact arrangement which makes them suitable for automotive. In one embodiment, a patch antenna comprises a flat, square radiating patch, a feed line for feeding a signal to the patch or for receiving a signal from the patch, if it is a receiving antenna rather than a transmitting antenna and a ground plane disposed beneath the patch and separated from it by a dielectric which in some embodiments may be air.
The feed line may comprise a microstrip disposed on one side of a substrate, or a strip line disposed in the middle of two substrates joined face to face the strip line being formed on one of the substrates with two opposing ground planes formed on the opposing outside surface of each of the substrates, respectively.
Low‐cost multi‐layer parasitic patch antenna array for 79 GHz automotive radar applications
The "length" of a patch antenna generally refers to the distance between the radiating edges of the patch. Thus, for example, in a square patch, this would be the length of a side of the square. In other. The radar system 20 is provided in one embodiment in a pulsed Doppler. The TX-antenna 27 may include, for example, a pattern switch The RX-antenna 26 may include, for example, a pattern switch It will be appreciated that other operation modes e. The antenna beam configuration may be controlled by the RX-pattern switch The RX-pattern switch 25 may include, for example, a pair of PIN switch diodes not shown , or a monolithic microwave integrated circuit MMIC switch chip to switch between the two different antenna beam.
In other embodiments, the radar system may include a plurality of RX antennas and a plurality of TX antennas. In some embodiments, a mid-range radar may have a detection range up to about 80 meters, though other ranges are also contemplated. In addition, it will be appreciated that although the structure is described in relation to an RXM application, the structure is not limited to such applications. In some embodiments, an end-feeding patch resonator 30 is associated with a plurality of radiation patches 32A-D. In the illustrated embodiment, each of the radiation patches 32A-D may have a square configuration with side lengths "L.
For the rectangular radiation patches 32A-D, the length is chosen for the resonance, while the width is chosen for the impedance matching. In addition, although the illustrated embodiment shows four radiation patches 32A-D, greater or fewer radiation patches may also be used. In other embodiments, the radiation patches 32A-D are non-resonant patches. The resonator portions 34A, B may be positioned to underlie at least a portion of each of the four radiation patches 32A-D. As illustrated, first resonator portion 34A underlies a portion of patches 32A and 32B, while second resonator portion 34B underlies a portion of patches 32C and 32D.
As can be seen, near the second ends 42 of the resonator portions the end feeding portion 36 splits into first and second notch segments 44A, B. In the illustrated embodiment, these notch segments 44A, B are "L"-shaped so they can connect to the second ends 42 at a substantially perpendicular angle.
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It will be appreciated, however, that the segments 44A, B could alternatively be straight so as to connect to the resonator portions 34A, B at an angle substantially parallel to the second ends Notably, the disclosed feeding portion 36 may act as an impedance transformer, in which all of the dimensions of the end-feeding portion 36, including length "EFL," width "EFW," and the geometry of the notch segments 44A, B, the extension distance "NED" as well as the gaps "EFG" between elements, can be adjusted to obtain a desired inductance and capacitance of the feed This ability to adjust the geometry of the end feeding portion 36 provides substantial impedance matching flexibility, which may eliminate the need to incorporate additional impedance matching components or structure to obtain a desired performance.
For the illustrated simulation, the end-feeding patch 30 and its feeding transmission line 36 are assumed to be positioned in the sub-layer about 0. The four radiation patches 32A-D are assumed to be positioned on a 0. As it can be seen from Fig.
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As will be appreciated, the RF feed energy is coupled through a slot 56 in the ground plane 46 to the array feeding network The feed slot 56 may be coupled to an RF drive signal, and may capacitively drive a signal on the end-feeding patch As shown, the slot structure 66 includes first and second slot portions 66A, 66B combined as a "narrow cross"-shape. In some embodiments, these slot portions 66A, 66B are formed in the ground plane see, e. The resulting "narrow cross"-shape may provide a notched bandwidth for matching over a wide bandwidth. In addition, the slot structure 66 is capable of maintaining a desired frequency bandwidth and high energy transfer efficiency from the RF source 68 and transmission line stub 67 to the RF feeding network Thus, in-line phase adjustment may be provided for the disclosed design.
Such in-line phase adjustment uses the forwarding distribution transmission line 70 as part of the phase adjustment, and combines a section of the returning trace 74 to achieve an overall phase compensation value for the even phase excitation of the radiation patches 32A-D. In Fig. This is an. Since the feeding network 76 is positioned between the ground plane 46 Fig. Thus, the disclosed serial distribution structure 76 reduces such impact.
In addition, the disclosed serial distribution structure 76 makes it easier to implement a coupling structure from the RF-circuit 68 to the feeding network 70 by using a single slot 66 structure for each antenna array, and therefore the leakage and interference from the slot 66 can be minimized. The serial distribution structure 76 provides desired coupling between the RF circuit 68, distribution transmission lines 70, and the individual patch antenna structures 28 via feed structures 38, 78, It will be appreciated, however, that such an arrangement is not limited to RXM arrays, and can be used in a variety of array.
The RXM array includes a 12 x 12 array of resonant radiation elements 32A-D fed by a 6 x 6 array of feeding patches coupled to serial distribution network In some. In an exemplary embodiment, the RXM array may be fit onto a single board 82 having a dimension of about 2.
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The azimuth and elevation patterns of the RXM antenna array are illustrated in Figs. As can be seen, the measured sidelobe levels of the RXM antenna radiation patterns are all below dB for both the azimuth and the elevation patterns at frequency lower than GHz. This indicates clearly that the leakage radiation from the feeding network 76 and the slot 66 is very small and does not have significant impact on the antenna patterns. The measurement data also show that the half-power beam width HPBW of both the azimuth and the elevation patterns are about degree.
Related Antenna Arrays and Automotive Applications
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