S-band Patch Research Articles

Effect of (Ba1/3Ta2/3)4+ substitution on microstructure, bonding properties and microwave dielectric properties of zirconium-cerium molybdate ceramics and the fabrication of S-band patch antennas

In this study, Ce2[Zr1x(Ba1/3Ta2/3)x]3(MoO4)9 (CZ1xTx, x = 0.01 ∼ 0.1) ceramics were synthesized via the solid-state method at temperatures ranging from 650 °C to 850 °C. XRD and Rietveld refinement analyses revealed that CZ1xTx ceramics exhibit a single phase with the space group R3-c, and the cell volume increases with higher doping content. SEM results indicate that CZ0.98T0.02 ceramics exhibit a highly regular and uniform grain shape. The CZ0.98T0.02 ceramics displayed optimal performance at 800 °C, exhibiting εr = 10.40, Q×f = 76,893 GHz, and τf = 14.61 ppm/°C. Additionally, the P-V-L theory was employed to establish correlations between ceramic chemical bonds and performance attributes. The results showed that the Ce-O bond predominantly influences εr while the Mo-O bond correlates with Q×f and τf. Furthermore, far-IR reflection spectra unveiled ion displacement polarization as the primary mechanism in CZ1xTx ceramics. Finally, based on CZ0.0.98T0.02 ceramics, a patch antenna applicable to the S-band was designed and fabricated, evidencing the vast potential of this ceramic in industrial applications.

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

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.

A Curved 3D-Printed S-Band Patch Antenna for Plastic CubeSat

The new space economy paradigm demands for cost-effective systems for its development. Plastic CubeSats are appealing candidates. To enable the use of this new generation of space systems, the challenge of designing suitable communication sub-systems must be faced. In this work, a 3D-printed ABS antenna easily embeddable in a plastic CubeSat is proposed. The 3D-printed material has been characterized in terms of dielectric, mechanical and thermal properties, and the compliance with space requirements has been assessed. In particular, thermogravimetric and calorimetric tests have been carried out. Static and dynamic mechanical analysis were performed. To comply with the stringent weight and space requirements, the unique antenna design of a curved stacked patch has been proposed. The patch covers the uplink (2.025–2.11 GHz) and downlink (2.2–2.29 GHz) bands for Telemetry Tracking and Command (TT&C) applications, with an overall bandwidth of about 300 MHz (14%). Additionally, taking advantage of the curved shape, the proposed antenna shows a size reduction of the resonant length of about 34%. The size of the antenna is 71.5 x 71.5 × 13 mm3 and is characterized by a weight of only 51 g. Also, in silico tests, by relying on the measured physical properties and a non-linear numerical model, have been carried out to assess the performances of the final antenna layout during a typical CubeSat mission. The proposed design strategy could be used to develop plastic CubeSats embedding performing antennas.

Low-Cost Dual-Band Multipolarization Aperture-Shared Antenna With Single-Layer Substrate

A novel dual-band multipolarization (DBMP) aperture-shared patch antenna with a single-layer substrate is proposed. The proposed DBMP antenna consists of a P-band rectangular patch antenna and an S-band circular patch antenna, in which the S-band patch is inserted into the P-band patch. The two feeding ports of the P-band antenna are fed through a 180° bridge to produce a linearly polarized (LP) mode. The S-band antenna also has two feeding ports; when only one port is fed, the antenna generates an LP mode; when the two ports are fed using a 90° bridge, the antenna can generate a left-handed circularly polarized or a right-handed circularly polarized mode by changing the input phases of the feeding ports. The entire antenna is fabricated and tested based on the optimized structure dimensions. The measured results match well with the simulated results. It is obtained that the antenna can achieve a bandwidth of 33.3% for the P-band and 16.4% for the S-band while the return loss is larger than 10 dB. Measured port isolation for both bands is better than -20 dB, and the 3 dB axial-ratio bandwidths in the S-band can completely cover the impedance bandwidth range when using a 90° bridge.

Dual‐band dual‐polarised microstrip antenna with improved inter‐port isolation

This Letter presents the development of a dual linearly polarised microstrip antenna for S- and C-band with improved isolation and bandwidth. The antenna is dual linearly polarised at each of the bands. The S-band patch is proximity coupled to two orthogonal feed lines, whereas the C-band patches are aperture coupled to other two mutually orthogonal feed lines. The antenna results in an impedance bandwidth ≥ 3.65% with an isolation ≥ 26 dB at the S-band ports. At the C-band ports, it also displays an isolation ≥ 45 dB over the entire operating bandwidth of ≥ 21%. All these results are improved compared to the earlier reported investigations.

Micromachined S-band patch antenna with reduced dielectric constant

A generic dielectric constant reduction method for silicon substrates is presented in detail along with a process description to produce variable dielectric layers for planar antennas. Virtually any dielectric constant below the value for solid silicon 11.9 can be produced down to the limit of structural durability. A first-order volumetric average yields a dielectric constant of 3.8 for the following bonded micromachined silicon substrates; small honeycomb cells with wall thickness of 16 μm and inner wall length of 87 μm are etched using deep reactive ion etch (DRIE) to 475 μm depth in each of two 525 μm 4 in. high ohmic wafers. These two wafers are bonded together with the etched side of both wafers facing each other. A manufactured coaxial-fed disk-patch S-band antenna illustrates the method to reduce the dielectric constant for a circular zone with a diameter of 50 mm. The antenna is designed for a center frequency of 2.5 GHz based on a lossless substrate with a dielectric constant of 3.8. Adjusting the simulation model to fit the measured values of the antenna indicates a dielectric constant of 2.2, a dielectric loss tangent of 0.002, a bulk conductivity loss of 0.006 S/m, and a resonance frequency of 3.2 GHz. A low frequency analysis in the interval 200–500 MHz with a lumped element model and a low frequency formula for the capacitance between the patch and ground plane indicates a dielectric constant in the order of 2.7–2.8. Based on measurements in an SEM, a corrected average dielectric constant is found to be 2.9. This correction is due to thinner walls than expected in the manufactured honeycomb structure. Antenna lobe characteristics have been measured with a half-power beamwidth of ∼76° in both the E-plane and H-plane at 3.2 GHz.