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1. Grating Lobe Mitigation in Scanning Planar Phased Array Antennas

   https://doi.org/10.1109/PAST43306.2019.9020996  

   Iqbal, Zabed; Pour, Maria (March 2020, 2019 IEEE International Symposium on Phased Array System & Technology (PAST))

   null (Ed.)

   This paper presents the grating lobe reduction in a planar phased array antenna with a rectangular lattice and large element spacing in the order of one wavelength for scan angles up to ±45°. A dual-mode circular microstrip patch antenna is considered as the constitutive element of the phased array, in which two different transverse magnetic modes are exploited simultaneously. The numerical analysis shows that the achieved grating lobe reduction is well below 25 dB for scan angles up to ±45° with large element spacing in the order of one wavelength. 

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2. A Multi-Band Circularly Polarized-Shared Aperture Antenna for Space Applications at S and X Bands

   https://doi.org/10.3390/electronics12214439  

   Kabir, Syed Salman; Khan, Mehedi Hassan; Latif, Saeed I. (November 2023, Electronics)

   In this article, a compact multiband antenna design and analysis is presented with a view of ensuring efficient uplink/downlink communications at the same time from a single antenna for CubeSat applications. This design shares the aperture of an S-band slot antenna to accommodate a square patch antenna operating in the X-band. Shared aperture antennas, along with an air gap and dielectric loading, provided good gain in both frequency bands. The S-band patch had an S11 = −10 dB bandwidth of 30 MHz (2013–2043 MHz, 1.5%), and the X-band antenna demonstrated a bandwidth of 210 MHz (8320–8530 MHz, 2.5%). The Axial Ratio (<3 dB) bandwidth of the slot antenna in the S-band is 7 MHz (2013–2020 MHz, 0.35%), and it is 67 MHz (8433–8500 MHz, 0.8%) in the case of patch antenna in the X-band. While the maximum gain in the S-band reached 7.7 dBic, in the X-band, the peak gain was 12.8 dBic. This performance comparison study shows that the antenna is advantageous in terms of high gain, maintains circular polarization over a wideband, and can replace two antennas needed in CubeSats for uplink/downlink, which essentially saves space. 

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3. A Wideband Stacked Patch-Patch Antenna with Hybrid Perturbations for Circular Polarization

   https://doi.org/10.1109/APS/URSI47566.2021.9703820.  

   M. M. Hossain, S. S. (February 2022, 2021 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (APS/URSI))

   This paper presents a wideband circularly polarized antenna for small satellites to be used with NASA Near- Earth Networks (NEN). This single-fed stacked antenna utilizes the electromagnetic coupling concept and is usable with a duplex transceiver. The circularly-polarized antenna employs hybrid perturbations on stacked patches and covers NASA NEN’s both uplink and downlink frequencies, thus replacing the conventional requirement of two separate antennas. It provides a notable wide axial ratio (AR) < 3 dB bandwidth of 1.16 GHz from 7.02 GHz to 8.18 GHz (15.3%). The optimized patch dimensions provide 34.6% VSWR ~ 2 bandwidth from 6,525 MHz to 9,253 MHz. The overall antenna size is 17 mm × 17 mm × 6.6 mm, and has a peak gain of 7.9 dBi. This proposed antenna will overcome solar cell space constraint on smallsat’s outer wall by saving at least 50% area required by the conventional two-antenna method. 

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4. Hybrid Perturbations in Stacked Patch–Ring Circularly Polarized Microstrip Antennas for CubeSat Applications

   https://doi.org/10.1109/MAES.2022.3141436.  

   M. M. Hossain, S. I. (February 2022, IEEE aerospace and electronic systems magazine)

   A hybrid perturbation scheme is used in this article to achieve wide axial ratio (AR) bandwidth and beamwidth from circularly polarized (CP) microstrip patch–ring antennas using a single probe feed. Perturbations in the diagonal corners of a square ring and a square patch arranged in a stacked configuration are introduced to achieve the circular polarization. First, an enhanced AR bandwidth is obtained when a combination of a square ring and a square patch with negative perturbations is used as parasitic and driven elements, respectively. Next, circular polarization with wider AR bandwidth, wider beamwidth, and lower cross-polarization is obtained when a combination of a driven square patch with positive perturbation and a parasitic square ring with negative perturbations, termed as hybrid perturbations, is used. This antenna has a footprint suitable for small satellite applications (e.g., CubeSats) and its operating frequencies cover the allocated S-band downlink frequencies of NASA Deep Space Network and NASA Near Earth Network. 

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5. Wideband Patch Antenna with Modified L-Probe Feeding for mmWave 5G Mobile Applications

   https://doi.org/10.3390/electronics13163119  

   Lee, Woncheol; Won, Hoyun; Hong, Yang-Ki; Choi, Minyeong; An, Sung-Yong (August 2024, Electronics)

   This paper presents a wideband low-profile dual-polarized patch antenna with helical-shaped L-probe feeding (HLF) for mmWave 5G mobile device applications. Parametric studies on the HLF structure are performed to identify the optimal specifications. As a result, the optimized antenna achieves a wide bandwidth of 5.4 GHz (24.2–29.6 GHz), good isolation > 18 dB between ports, and 5.1 dBi of good peak realized gain, which is experimentally verified with a 10× upscaled antenna. In addition, various one × four phased arrays with different port configurations and beamform capabilities are designed and simulated for the peak realized gain. The designed antenna array shows a high peak realized gain of 10 dBi, high isolation of 15 dB between the ports, and a small substrate thickness of 0.048λ0 (λ0 is the wavelength of 24.25 GHz). Compared to the state-of-the-art antennas, the designed dual-polarized antenna can operate in the frequency ranges of 24.25–29.6 GHz, including n257, n258, and n261 of the 5G new radio frequency range 2. 

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