Fig 5 - uploaded by Gerald Artner
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A cavity prototype with floor cutout that allows measurements of multiple antenna systems and antennas on different positions.
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The number of antennas mounted on vehicles keeps growing. Antennas in hidden modules will replace or supplement antennas in shark-fin modules. Chassis antenna cavities were recently proposed as large antenna modules, which can be built, and concealed, inside the vehicle chassis. Recent results of multiple antennas inside a chassis antenna cavity ar...
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... The exchange- able aluminum plates can be laser-cut and allow placement of antennas at different locations and MIMO configurations inside the cavity. Before their application the influence of the exchangeable bases onto antenna measurements needs to be verified. Measurements of more advanced antenna setups will continue after verification. Fig. 5 shows a photograph of a CFRP cavity prototype cut by waterjet for exchangeable cavity bases. With the exchangeable bases the antennas are also fastened inside the cavity for drive tests. It should be noted, that this is only required during development. For mass- production the antennas and their locations are already fixed, and ...
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Citations
... The aluminum cavity is shown in Fig. 2b. Multiple antennas inside such a cavity are investigated in [36], where influence on the gain patterns is found due to the proximity of the antennas inside a single cavity. ...
An automotive concept for vehicular communications is proposed that utilizes the potential of the roof area for antennas. Antennas are distributed in cavities and on shelves in the center and on the front and rear roof ends. The arrangement of antennas on the roof allows better radiation to the front and back of automobiles than shark-fins and single cavities. Combining several modules provides space for further antennas, sensors and integrated front-ends, as well as better spatial separation for multiple-input multiple-output (MIMO) arrays beyond 5G, and cooperative connected and automated driving. A prototype was developed and built into a car chassis. Measured data were analyzed and evaluated in the view of coverage for vulnerable road users and on correlation for MIMO.
... An antenna for vehicle-to-any (V2X) communication and a wideband conical monopole antenna in such a large automotive chassis antenna cavity are presented in [6]. A pattern reconfigurable antenna inside a cavity is measured in [7] and a multipleantenna configuration in [8]. A chassis antenna cavity at the car's roof edge directly above the windshield is presented in [9], and it is shown that this position substantially increases radiation towards lower elevation angles. ...
... The simulation results are compared to measurements of a cavity prototype that is made from CFRP. It is the same chassis cavity, which is used in [5]- [8]. The cavity has a size of about 150 × 500 mm 2 . ...
Cavities built into the vehicle chassis have recently emerged as receptacle for hidden antennas. In the automotive sector they potentially replace the roof mounted shark-fin antenna modules. Simulation models for chassis antenna cavities are critical, because they must both accurately predict antenna performance, while staying computationally reasonable. Moreover, if the chassis of electric cars, airplanes and boats are built with carbon fiber reinforced polymer, then a model for the composite laminate is required. In this paper a simple simulation model for chassis antenna cavities is developed. The carbon fiber composite material is modeled as a linear, homogeneous and isotropic conductor, and several cavity geometry details are omitted. Simulation results are in good agreement with measurements in the frequency band at 5.9 GHz for intelligent transport systems.
... Measurements of multiple antennas inside a chassis antenna cavity are published in [12] and this section is based on this work. ...
... Measurement results are shown in Fig. 3.33. The vertical cut along the short cavity side is omitted, as only minor changes in pattern are found [12]. The vertical cut along the long cavity side (Fig. 3.33a) shows only small changes in the conical monopole antenna's gain pattern towards low polar angles θ. ...
... Results for 5.9 GHz are available in [12]. The number of possible antenna configurations are limited during the prototyping stage, as each antenna is c 2017 IEEE, reprinted with permission from [12]. ...
Vehicles increasingly communicate with their surrounding environment. They are no longer mere receptors of radio broadcasts, but actively exchange information with their surroundings. These communicative vehicles will radically change our view on transportation. They enable cooperative driving and are used as mobile access nodes for telecommunication networks – no longer just moving combustion engines. Extended radio frequency hardware is the technical basis for this increase in wireless vehicular communication. The critical part of the communication system are the antennas, as they have to be placed outside the vehicles hull and therefore become interdependent with vehicle design. This dissertation examines the influence of carbon fiber reinforced polymer on vehicular antennas and the development of an antenna cavity for vehicles. Together these findings secure enough construction space for antennas in future light-weight constructed vehicles.
Electric cars are increasingly constructed with chassis made from Carbon Fiber Reinforced Polymer (CFRP). This requires the characterization of these materials for vehicular antennas. Material samples are measured inside rectangular waveguides and the material parameters are estimated with the Nicolson-Ross-Weir method. Measurement results show, that the electric conductivity of CFRP with twill-weave and CFRP with fiber shreds on the surface are approximately isotropic in the investigated frequency range around 6 GHz. This motivates the use of recycled CFRP. Sustainable materials are in this case also optimal for antenna applications. The transition from metal to CFRP chassis influences monopole antennas, which are currently widely used in automotive applications, as these antennas use chassis parts as ground plane. Both narrowband and wideband monopole antennas are measured on ground planes manufactured from different CFRP.
A cavity for vehicular antennas is designed, manufactured, measured and evaluated. The cavity is larger than currently used roof-mounted shark-fin antenna modules and can be manufactured as part of the chassis and hidden therein. As proof that the production of such a cavity is realizable for electric cars, a prototype is built from CFRP. To show feasibility for antennas, several antennas are measured and evaluated inside the cavity. Investigated antennas include a monopole antenna and an inverted-F antenna, both manufactured as laser-structured injection molded parts; a broadband conical monopole antenna and intelligent antennas with reconfigurable radiation patterns. Detailed measurement based evaluations of the antennas inside the cavity show that the cavity concept is feasible. Influences of the cavity on the functionality of the antennas inside are also analyzed by measurement. Strong influences on the antennas occur at frequencies in the high single-digit gigahertz range, where the cavity is electrically large.
