An official website of the United States government
This article presents a new notch steering scheme for hybrid beamforming transmitters (TXs) aimed at suppressing spatial interference, thereby enhancing the signal-to-interference-plus-noise ratio (SINR) to support spatial multiplexing. Built upon existing phased arrays, this scheme integrates an auxiliary-path vector modulator (VM) into each antenna element, which in turn, forms an interference-canceling beam. By spatially combining the array factors (AFs) of the main beam and the interference-canceling beam, a deep spatial notch is created while ensuring minimal main-beam power degradation. Unlike the conventional zero-forcing method that requires matrix inversion in digital for spatial notch creation, our scheme enables the computation of antenna weights in analog, significantly reducing the computational cost and latency. Leveraging this new notch steering scheme, we develop a 28-GHz four-element fully connected (FC) hybrid beamforming TX array using the GlobalFoundries 45-nm CMOS Silicon-on-Insulator (SOI) process. It is capable of simultaneously transmitting two independent, wideband data streams (DSs) in the same polarization toward two directions. In probing-based measurements, each TX channel delivers 19.7-dBm OP1 dB, 20.4-dBm PSAT , and 30.6% peak power-added efficiency (PAE) at 29 GHz, demonstrating state-of-the-art TX linearity and efficiency. In over-the-air (OTA) measurements, the packaged TX array achieves 29.8-dBm EIRP1 dB and is able to steer a spatial notch outside the −10-dB beamwidth of the main beam, with a notch depth of >35 dB and a main-beam power degradation of < 0.8 dB. Moreover, in spatial multiplexing demonstrations, the TX array is capable of transmitting a 400-MHz 64-quadrature amplitude modulation (QAM) signal to the intended receiver (RX) in the first DS, while suppressing the co-channel continuous-wave or wideband modulated interference created by the second DS with a high SINR.
more »
« less
Highly Miniaturized and Wideband 3-dB Quadrature Hybrid Using Slow-Wave Coupled Line
A novel highly miniaturized wideband quadrature hybrid using slow-wave technology is proposed in this paper. In order to reduce the size of conventional branch-line/coupled-line couplers, a unique structure is utilized based on two layers of crossing strips with densely interconnecting vias. This structure makes full use of the electrical coupling and magnetic coupling in the slow-wave structure, and enhances the mutual inductance effect between parallel vias, which successfully leads to enhanced coupling strength that enabling the wideband 3-dB quadrature hybrid. Importantly, 99.4% of size reduction has been achieved as compared to conventional three-section branch-line counterpart while maintaining an equally good performance. The achieved relative planar area is only 0.003A2, which is orders-of-magnitude improvement over state-of-the-art.
more »
« less
- Award ID(s):
- 1914875
- PAR ID:
- 10347380
- Date Published:
- Journal Name:
- IEEE MTT-S International Microwave Symposium (IMS)
- Page Range / eLocation ID:
- 247 to 250
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract This article presents a nonlinear leaky wave antenna (LWA) with frequency dependent parametric radiation based on a fundamentally slow‐wave transmission line (TL) structure. Unlike a conventional LWA that radiates at the excitation frequency, the radiation for the proposed travelling wave structure relies on the parametric frequencies based on the injected pump signals. The proposed nonlinear fundamentally slow wave structure utilizes a periodic sharply bend TL loaded by varactor diodes as nonlinear elements. By utilizing then = −1 spatial harmonic, the fundamentally slow wave structure can enter the leaky wave region at higher frequencies, where the parametric radiation results from the bifurcation of the injected pump signals. Such TL‐based nonlinear LWA reduces the design complexity and fabrication difficulty. The resulting parametric frequency radiation can be used for beam steering, which provides additional degree of design freedom.more » « less
-
This paper presents a new way of designing multi-mode switchable power amplifier without relying on any extra tuning elements. By operating the RF GaN transistor as a switch (digital) or amplifier (analog), it enables three different modes within a quadrature-balanced load-modulation architecture, including series/parallel Doherty and hybrid load modulated balanced amplifier (H-LMBA), which can be optimally configured according to different load conditions. Based on this new method, an intrinsically mode-switchable load-modulation PA is designed with GaN transistors and branch-line quadrature coupler at 1.7 GHz. Together with the unique harmonic-tuned method, the nominal mode of H-LMBA (for matched condition) achieves a high-order load modulation with > 62% measured efficiency across a 10-dB output back-off (OBO) range. Efficient performance is also demonstrated at series/parallel Doherty modes, which are configured with exchangeable main/auxiliary roles and dedicated switch settings offering mismatch resilience.more » « less
-
We investigate the influence of repulsive vector interactions and color superconductivity on the structure of neutron stars using an extended version of the field correlator method (FCM) for the description of quark matter. The hybrid equation of state is constructed using the Maxwell description, which assumes a sharp hadron-quark phase transition. The equation of state of hadronic matter is computed for a density-dependent relativistic lagrangian treated in the mean-field approximation, with parameters given by the SW4L nuclear model. This model described the interactions among baryons in terms of σ, ω, ρ, σ*, and ϕ mesons. Quark matter is assumed to be in either the CFL or the 2SC+s color superconducting phase. The possibility of sequential (hadron-quark, quark-quark) transitions in ultra-dense matter is investigated. Observed data related to massive pulsars, gravitational-wave events, and NICER are used to constrain the parameters of the extended FCM model. The successful equations of state are used to explore the mass-radius relationship, radii, and tidal deformabilities of hybrid stars. A special focus lies on investigating consequences that slow or fast conversions of quark-hadron matter have on the stability and the mass-radius relationship of hybrid stars. We find that if slow conversion should occur, a new branch of stable massive stars would exist whose members have radii that are up to 1.5 km smaller than those of conventional neutron stars of the same mass. Such objects could be possible candidates for the stellar high-mass object of the GW190425 binary system.more » « less
-
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.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/IMS19712.2021.9575013
