Filtering Antenna Array Research Articles

A low‐profile high‐gain filtering patch antenna with harmonic suppression

AbstractA compact high‐gain filtering patch antenna with harmonic suppression characteristic is proposed. The antenna mainly contains a coupled transmission line and a central rectangular patch. The capacitive coupling between the coupled transmission line and the rectangular patch generates a radiating null at high frequencies. Then, acrossing the hybrid coupling principle, the structure of the microstrip‐to‐slotline transition builds two coupling paths, which generate a radiating null at low frequencies. In addition, two vertical slots are carved into the rectangular center patch to truncate the lateral current. That removes the higher order resonant modes and suppresses the parasitic passbands at high frequencies outside the passband. A fabricated 2 × 2 filtering antenna array is measured, showing a bandwidth up to 3.9% (8.68–9.03 GHz), a peak gain of 14.43 dBi, and two near‐band radiation nulls located at 8 and 9.55 GHz, demonstrating good radiation performances and an isolation of 25 dB.

Filtering Antenna Array Based on Strongly Coupled Radiant Metal Block

Filtering Antenna Array Based on Strongly Coupled Radiant Metal Block

A Shared-Aperture Linearly/Circularly-Polarized Filtering Antenna Array with Low Profile

A Shared-Aperture Linearly/Circularly-Polarized Filtering Antenna Array with Low Profile

Filtering Antenna Array Based on Corrugated Vivaldi Elements

Filtering Antenna Array Based on Corrugated Vivaldi Elements

Conformal transmitarray based on metasurface fed by miniaturized filtering antenna

AbstractTo realize the requirements of 5G MIMO technology for high‐performance antennas, a novel high‐gain transmissive array antenna with conformal capability is designed in this study. The antenna consists of a single‐layer dielectric‐based conformal transmission array and a substrate‐integrated waveguide filter antenna. The transmission array is composed of a cross element and spiral elements that can achieve conformal capability. Each metasurface element is a single‐layer medium, and the same metasurface patches above and below are connected by four metal pillars. A filter antenna array fed by a substrate integrated with a waveguide fed by small‐scale low‐temperature cofired ceramic technology is used as the feed antenna of the transmission array. The physical test results are consistent with the simulation results, and the directivity of the antenna is greatly improved. The frequency range where the reflection coefficient S11 is less than −10 dB is 26.6–29.1 GHz. At the center frequency of 28.0 GHz, the gain of the conformal antenna array is greatly improved, and the peak gain is increased from 8.2 to 24.5 dB. The sidelobe level is substantially suppressed. Its high gain and beamforming characteristics make it have a high application value in 5G MIMO technology.

Broadband Dual-Polarized Differential-Fed Filtering Antenna Array for 5G Millimeter-Wave Applications

This article presents a novel broadband dual-polarized filtering patch antenna array using low-temperature cofired ceramic (LTCC) process for 5G millimeter-wave (mmW) applications. The filtering antenna element is implemented using a ± 45° polarized patch antenna fed by two pairs of differential L-type probes. An additional square ring and open strips are connected to each probe, resulting in radiation nulls and realizing the lower/upper stopband rejection level over 24 dB with skirt selectivity. The cross coupling among these structures not only introduces filtering responses, but also contributes to broadening the passband of 24.25–29.5 GHz covering 5G n257/n258/n261 bands. The antenna performance is validated by equivalent circuits based on transmission line models, which reveals clearly the principles of filtering antenna step by step and provides guidelines for further designs. The proposed filtering antenna element is expanded to a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times 4$ </tex-math></inline-formula> filtering antenna array with shunt-fed feeding networks. The spacing between elements is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.48~\lambda _{0}$ </tex-math></inline-formula> . The measured results demonstrate that the array performs good filtering characters including high stopband rejection, high selectivity, and wide upper stopband up to 40 GHz, where the antenna efficiency (considering radiations from all the directions) is less than 5%. In addition, the differential feeds provide symmetric radiation patterns with low cross-polarized counterparts. Compared with other reported works, the proposed filtering antenna/array has excellent performances of wideband, high stopband rejection and wide upper stopband for potential 5G mmW applications.

Slot Antenna Array with Integrated Filter for WLAN Application at 5.2 GHz

This paper deals with the design of a $$2\times 2$$ Integrated Filter Antenna array working at 5.2 GHz for IEEE 802.11a WLAN application. The filtering action is incorporated into the conventional antenna array, rendering enhanced selectivity and sharper gain roll-off than the conventional approach. An equivalent circuit model is extracted to validate the working of the proposed design. Fractional band width of $$3.0\%$$ around 5.2 GHz (ranging between 5.15 and 5.31 GHz) and maximum gain of 11.11 dBi is obtained through this design.

X-Band Waveguide Filtering Antenna Array With Nonuniform Feed Structure

This paper proposes a novel design approach for a filtering antenna, which contains an array of 4 by 2 waveguide aperture radiation elements. Coupling matrix theory is introduced in this paper to synthesize the multiple coupled-resonators circuit. Unequal amplitude excitation is applied to the $4 \times 2$ elements so as to obtain a low sidelobe level. To demonstrate the concept, an X-band antenna array is designed and fabricated using a three-layer waveguide structure. Measured results show that the filtering antenna array can achieve a gain of more than 15.58 dBi and a radiation efficiency of higher than 90% over the passband (9.91–10.1 GHz). The sidelobe level is −18.3 dB in the ${H}$ -plane and −21.1 dB in the ${E}$ -plane.