Analysis and Design of a mm-Wave Wideband LTCC Patch Antenna for 5G Applications

Date
2022-12-23
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Abstract
Fifth-generation mobile network (5G) has been planned to meet society's strong data advancement and accessibility. Since the current Long-Term Evolution (LTE) spectrum, i.e., 4G, is crowded and fragmented under 6 GHz, millimeter-wave frequency bands have attracted more interest in deploying 5G networks. The vast amount of unused spectrum in the mm-wave region can support higher data rates required in future mobile broadband access networks. For such significant data rates, wideband systems are required. An appropriate choice is an aperture-coupled patch antenna offering large bandwidth, good cross-polarization, and higher efficiency than conventional microstrip antennas. In mm-wave bands, the losses caused by materials, fabrication tolerances, measurement methodologies, and interconnections between feed lines and the antenna impact the overall performance of the antenna. Accordingly, the interest in fabricating mm-wave antennas using Low-Temperature Co-fired Ceramic (LTCC) is increasing. The LTCC fabrication process, in addition to lower substrate loss and higher fabrication tolerance, enjoys flexibility in realizing an arbitrary number of layers and ease of integration with other circuit components. In this work, a new aperture-coupled patch antenna with wide bandwidth at Ka-band and stable radiation patterns at 28 GHz for 5G applications has been designed, implemented, and tested with Dupont 9K7 LTCC technology. A parasitic patch, embedded air cavity, and large-size aperture improved the bandwidth. Moreover, the embedded air cavity enhanced the gain and reduced losses caused by the surface wave in the mm-wave band. A stripline feed was designed and used, allowing the antenna to be more easily integrated with a beamformer IC in the active array configuration. The impedance bandwidth achieved by the designed antenna is 32%, with a maximum gain of 9 dB at 28 GHz. A broadband Sub-Miniature-Push on Micro (SMPM) coaxial to stripline transition is also developed to feed the proposed antenna. A back-to-back configuration of the transition was fabricated and measured to validate the design. Experimental results showed a good agreement with the simulation results, with a return loss of better than 10 dB and an insertion loss of around 1 dB between 9 to 31 GHz.
Description
Keywords
mm-wave antenna, LTCC, aperture-coupled patch antenna, SMPM coaxial connector to LTCC stripline transition
Citation
Sadeghi, M. (2022). Analysis and design of a mm-wave wideband LTCC patch antenna for 5G applications (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.