A Compact, Dual-Band, Full-Duplex Conformal Filtering Antenna Array for Seamless Vehicular Connectivity

The continuous increase in demand for high-speed wireless systems in vehicular communication has led to the need for efficient, conformal, compact, and reliable antenna systems that simultaneously function in multiple frequency bands. Existing full-duplex filtering antennas mainly suffer from conformality, compact size, and vehicular connectivity, which limit their application on a vehicle. The article presents a compact dual-band full-duplex conformal filtering antenna array with a hairpin resonator, coupling topology for Sub-6 GHz Frequency Range (FR1) and vehicular application to address this issue. The two-port filtering antenna is widely used due to its high isolation and ability to operate simultaneously at different frequency bands. Such quality is used in full-duplex operation mode, which reduces the complexity in RF front-end systems. The proposed antenna has multi-functional abilities such as conformality, filtering characteristics, compact size, and full-duplex operations. It is evident from the analysis that the proposed antenna element works at its fundamental mode (TM
₁₁
) for the desired frequency band. To verify the concept, a 2 × 2 antenna array in planar and conformal conditions is designed and tested. All the measurement and simulation results are well in agreement, showing two full-duplex filtering channels of 3.41–3.76 GHz and 5.65–6.1 GHz for transmitting and receiving purposes, respectively. The offered antenna also shows excellent performance in port isolation, bandwidth, and gain. In the vehicular integration section, the ANSYS Savant simulation tool is used where the conformal array is mounted in the vehicle (roof, front, and rear bumper), and corresponding far-field characteristics are performed.