Proximal-Field Radiation Sensors for Dynamically Controllable and Self-Correcting Integrated Radiators

One of the major challenges in the design of integrated radiators at mm-wave frequencies is the generation of surface waves in the dielectric substrate by the on-chip antennas. Since dielectric substrates are excellent surface waveguides with a fundamental mode with no cutoff frequency, there is always some energy trapped in them due to the surface waves and the excited substrate modes. This phenomenon is a significant cause of reduced radiation efficiency for mm-wave integrated radiators. However, in this thesis, we use this as an opportunity. We show that the excited substrate modes in the dielectric substrate of an integrated antenna contain valuable information regarding its far-field radiation properties. We introduce Proximal-Field Radiation Sensors (PFRS) as a number of small sensing antennas that are placed strategically on the same substrate as the integrated antenna and measure electromagnetic waves in its immediate proximity. These sensors extract the existing information in the substrate modes and use it to predict the far-field radiation properties of the integrated antenna in real-time based on in-situ measurements in the close proximity of the antennas, without any need to use additional test equipment and without removing the antenna from its operating environment or interfering with its operation in a wireless system. In other words, PFRS enables self-calibration, self-correction, and self-monitoring of the performance of the integrated antennas. Design intuition and a variety of data processing schemes for these sensors are discussed. Two proof-of-concept prototypes are fabricated on printed circuit board (PCB) and integrated circuit (IC) and both verify PFRS capabilities in prediction of radiation properties solely based on in-situ measurements. Dynamically controllable integrated radiators would significantly benefit from PFRS, These radiators are capable of controlling their radiation parameters such as polarization and beam steering angle through their actuators and control units. In these cases, PFRS serves as a tool for real-time monitoring of their radiation parameters, so that without direct measurement of the far-field properties through bulky equipment the required information for the control units and the actuators are provided. Dynamically controllable integrated radiators can be designed using the additional design space provided by Multi-Port Driven (MPD) radiator methodology. After a review of advantages of MPD design over the traditional single-port design, we show that a slot-based MPD radiator would have the additional advantage of reduced exclusive use area compared to the original wire-based MPD radiator, through demonstration of a 134.5-GHz integrated slot-based MPD radiator with a measured single-element EIRP of +6.0 dBm and a total radiated power of -1.3 dBm. We discuss how MPD methodology enables the new concept of Dynamic Polarization Control, as a method to ensure polarization matching of the transmitter antenna to the receiver antenna, regardless of the polarization and orientation of the receiver antenna in space. A DPC antenna design using the MPD methodology is described and a 105.5-GHz 2x1 integrated DPC radiator array with a maximum EIRP of +7.8 dBm and a total radiated power of 0.9 mW is presented as the first demonstration of an integrated radiator with DPC capability. This prototype can control the polarization angle across the entire tuning range of 0 to 180 degrees while maintaining axial ratios above 10 dB, and control the axial ratio from 2.4 dB (near circular) to 14 dB (linear). We also demonstrate how simultaneous two-dimensional beam steering and DPC capabilities can even match the polarization to a mobile receiver antenna through a prototype 123-GHz 2x2 integrated DPC radiator array with a maximum EIRP of +12.3 dBm, polarization angle control across the full range of 0to 180 degrees as well as tunable axial ratio down to 1.2 dB and beam steering of up to 15 degrees in both dimensions. We also use slot-based DPC antennas to fabricate a 120-GHz integrated slot-based DPC radiator array, expected to have a maximum EIRP of +15.5 dBm. We also introduce a new modulation scheme called Polarization Modulation (Pol-M) as a result of DPC capability, where the polarization itself is used for encoding the data. Pol-M is a spatial modulation method and is orthogonal to the existing phase and amplitude modulation schemes. Thus, it could be added on top of those schemes to enable creation of 4-D data constellations, or it can be used as the only basis for modulation to increase the stream security by misleading the undesired receivers. We discuss how DPC antenna enables Pol-M and also present PCB prototypes for Pol-M transmitter and receiver units operating at 2.4 GHz.</p

A flexible phased array system with low areal mass density

Phased arrays are multiple antenna systems capable of forming and steering beams electronically using constructive and destructive interference between sources. They are employed extensively in radar and communication systems but are typically rigid, bulky and heavy, which limits their use in compact or portable devices and systems. Here, we report a scalable phased array system that is both lightweight and flexible. The array architecture consists of a self-monitoring complementary metal–oxide–semiconductor-based integrated circuit, which is responsible for generating multiple independent phase- and amplitude-controlled signal channels, combined with flexible and collapsible radiating structures. The modular platform, which can be collapsed, rolled and folded, is capable of operating standalone or as a subarray in a larger-scale flexible phased array system. To illustrate the capabilities of the approach, we created a 4 × 4 flexible phased array tile operating at 9.4–10.4 GHz, with a low areal mass density of 0.1 g cm^(−2). We also created a flexible phased array prototype that is powered by photovoltaic cells and intended for use in a wireless space-based solar power transfer array

Proximal-Field Radiation Sensors for Millimeter-Wave Integrated Radiators

Integration of Proximal-Field Radiation Sensors (PFRS) with mm-wave integrated radiators enables extraction of valuable information about their far-field radiation properties from the surface waves inside the substrate and the electromagnetic fields in close proximity of the radiating antennas. In this paper, we present a 72 GHz 2×1 integrated radiator array with four on-chip PFRS units to show proximal-field sensing capability in calculation of far-field radiation properties solely through on-chip measurement of proximal fields

Dynamic Polarization Control

Dynamic polarization control (DPC) is the method of setting the polarization of the far-field electric field generated by a radiating antenna entirely electronically in order to maintain polarization matching with the receiving antenna regardless of its polarization or orientation in space. This work implements a fully integrated 2 × 1 phased array radiator in 32 nm CMOS SOI at 105.5 GHz with DPC. The system consists of a central locking oscillator that phase locks oscillators within the core of each antenna followed by three amplification stages with variable gain that drive the antennas. By controlling the amplitude and phase of two orthogonal polarized subparts of each multi-port antenna, various far-field polarizations can be realized. The array is capable of beam steering, controlling the polarization angle across the entire tuning range of 0° to 180° while maintaining axial ratios above 10 dB, and controlling the axial ratio from 2.4 dB (near circular) to 14 dB (linear) in various directions of radiation. It radiates a maximum EIRP of 7.8 dBm with a total radiated power of 0.9 mW. To the best of the authors’ knowledge, this work presents the first integrated radiator with dynamically controllable polarization

Dynamic Polarization Control of Integrated Radiators

Dynamic Polarization Control (DPC) ensures polarization matching to the receiving antenna regardless of its polarization or orientation in space. A fully integrated 105.5 GHz 2×1 DPC multi-port driven radiator array with beam steering radiates linear polarization across the full polarization angle range of 0° to 180° maintaining axial ratios above 10 dB, and controls the axial ratio from 2.4 dB (near circular) to 13 dB (linear) in various directions of radiation and a maximum EIRP of 7.8 dBm

An Integrated Slot-Ring Traveling-Wave Radiator

Electromagnetic duality is used to design a multi-port traveling-wave slot-ring antenna with on-chip driver circuitry to create a fully integrated radiator. By creating a slot version of the multi-port driven antenna, the required exclusive use area of the antenna is significantly decreased, while still being able to perform impedance matching, power combining, and power transfer off chip through electromagnetic radiation in a single step. The driver core consists of an oscillator followed by three amplification stages. A split path inductor design was utilized to reduce the radiator's dependence on process variation in the metal stack while ensuring proper isolation between the four quadrature paths. The slot radiator has a simulated antenna efficiency of 39% and a measured single-element effective isotropic radiated power of 6.0 dBm with a total radiated power of -1.3 dBm at 134.5 GHz

An integrated traveling-wave slot radiator

A traveling-wave integrated slot radiator is designed using electromagnetic duality theory based off of the ring portion of a radial multi-port driven radiator to minimize the area required exclusively for the antenna. It is designed in 32 nm SOI CMOS and driven by a buffered quadrature VCO at 4 points to create the traveling wave that radiates out of the backside of the chip. It is measured to have a maximum EIRP of 6.0 dBm at 134.5 GHz with a total radiated power of -1.7 dBm while drawing 168 mW DC power

Proximal-field radiation sensors

Proximal-Field Radiation Sensors (PFRS) are introduced as a new set of tools to enable extraction of far-field radiation properties of integrated antennas from the surface waves inside their dielectric substrates. These sensors allow self-characterization, self-calibration, and self-monitoring of the radiation performance for both printed circuit board (PCB) antennas and integrated circuit (IC) antennas without any need to additional test equipment. In this paper, we explain how these sensors can be implemented and demonstrate how the far-field radiation properties can be determined from them. A PCB prototype consisting of two transmitting patch antennas and four integrated PFRS antennas is fabricated and tested to verify the concept and demonstrate the implemented sensors' capabilities to capture the radiation properties such as gain pattern, radiated polarization, and the steering angle of the antenna array as a few examples of radiation sensors applications