A 10-GHz Code-Modulated Interferometric Imager Using Commercial-Off-The-Shelf Phased Arrays

Chauhan, Vikas; Schönherr, Simon; Hong, Zhangjie; Floyd, Brian

doi:10.1109/mwsym.2019.8700850

Cited by 6 publications

(4 citation statements)

References 8 publications

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“…Above all, the proper characterization, calibration, and control of the array in OOB are most significant, since the phase and amplitude control in OOB could be quite different in order to steer beams accurately. We can utilize code-modulated interferometry (CMI) for this purpose [16]- [18]. In CMI, all elements in the array are modulated using unique codes and then the vector responses of all phase shifters in free space can be extracted in parallel using a simple scalar detector together with digital signal processing, which allows us to calibrate the array at any frequency.…”

Section: A Spectrum Monitoring and Signal Leakage Sensingmentioning

confidence: 99%

National Radio Dynamic Zone Concept with Autonomous Aerial and Ground Spectrum Sensors

Maeng¹,

Güvenç²,

Sichitiu³

et al. 2022

Preprint

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National radio dynamic zone (NRDZs) are intended to be geographically bounded areas within which controlled experiments can be carried out while protecting the nearby licensed users of the spectrum. An NRDZ will facilitate research and development of new spectrum technologies, waveforms, and protocols, in typical outdoor operational environments of such technologies. In this paper, we introduce and describe an NRDZ concept that relies on a combination of autonomous aerial and ground sensor nodes for spectrum sensing and radio environment monitoring (REM). We elaborate on key characteristics and features of an NRDZ to enable advanced wireless experimentation while also coexisting with licensed users. Some preliminary results based on simulation and experimental evaluations are also provided on out-of-zone leakage monitoring and real-time REMs.

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Section: A Spectrum Monitoring and Signal Leakage Sensingmentioning

confidence: 99%

National Radio Dynamic Zone Concept with Autonomous Aerial and Ground Spectrum Sensors

Maeng¹,

Güvenç²,

Sichitiu³

et al. 2022

Preprint

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“…Thus, it allowed experiments for imaging and avoided any complications associated with packaging, antenna design, assembly, digital programming. Thus, the 10 GHz approach has been pursued and been used for several prototypes in this chapter [Cha19]. One disadvantage of using 10 GHz hardware is bigger wavelength and thus lower resolution.…”

Section: Overviewmentioning

confidence: 99%

“…To test the feasibility of CMI using COTS phased arrays, first a 33-pixel, eight-element 10-GHz eight-element imaging system prototype is built as shown in Fig. 4.1 and 4.12 [Cha19].…”

Section: -Pixel Cots CMI Imaging Prototypementioning

confidence: 99%

PhD Thesis on Code Modulated Interferometric Imaging System using Phased Arrays

Chauhan¹

2021

Preprint

Self Cite

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CHAUHAN, VIKAS. PhD Thesis on Code Modulated Interferometric Imaging System using Phased Arrays. (Under the direction of Brian A. Floyd.) This work presents techniques which can allow low-cost phased-array receivers to be reconfigured or re-purposed as interferometric imagers, removing the need for custom hardware and thereby reducing cost. Since traditional phased arrays power combine incoming signals prior to digitization, orthogonal code-modulation is applied to each incoming signal using phase shifters within each front-end and two-bit codes. These codemodulated signals can then be combined and processed coherently through a shared hardware path. Once digitized, visibility functions can be recovered through squaring and code-demultiplexing operations. Provided that codes are selected such that the product of two orthogonal codes is a third unique and orthogonal code, it is possible to demultiplex complex visibility functions directly. As such, the proposed system modulates incoming signals but demodulates desired correlations.Firstly, we present the operation of the system, a validation of its operation using behavioral models of a traditional phased array and a benchmarking of the code-modulated interferometer against traditional interferometer using simulation results and sensitivity analysis. Secondly, for the proof of concept with a prototype, we present a simple CMI system operating in the license-free 60-GHz band using a four-element phased-array receiver developed for IEEE 802.11ad (WiGig) and packaged with compact antenna structures. The four-element 60-GHz phased array chip is wire-bonded onto a Rogers-5880 substrate board with on-board slot antennas, and a single 60-GHz output is measured using a power detector. This scalar measurement is then demodulated to obtain the interferometric visibilities.The four-element phased array is thinned to obtain a 13-pixel image and the system is

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“…Finally, the same CoMET infrastructure can be employed for chip, package, and freespace characterization and calibration. Code-modulated interferometry has been used for imaging in [11], [12], [13], [14].…”

Section: Introductionmentioning

confidence: 99%

Code-Modulated Embedded Test and Calibration of Phased-Array Transceivers

Hong

Chauhan

Schönherr

et al. 2021

IEEE Trans. Microwave Theory Techn.

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We present methods for built-in test and calibration of phased arrays using code-modulated embedded test (CoMET). Our approach employs Cartesian modulation of test signals within each element using existing phase shifters, combining of these signals into an aggregate code-multiplexed response, downconversion and creation of code-modulated element-toelement "interference products" using a built-in power detector, demodulation of correlations from the digitized interference response, and extraction of amplitude and phase per element using an equation solver. Rotated-axis methodology is discussed for accurate extraction of phase near the original 0/90/180/270 degree axes. Our techniques are demonstrated at board level for both receive and transmit modes using an eight-element 8-16 GHz phased array constructed using ADAR1000 chips from ADI. At 6 GHz, CoMET-extracted gain and phase are accurate to within 0.2 dB and 3 • compared to network-analyzer measurements. We then employ CoMET in a calibration loop to determinate optimum control settings at 6 GHz, outside the 8-16 GHz band for which the array was designed. We achieve seven-bit phase resolution with equalized gain. The root-mean squared gain and phase errors are improved from 0.8 dB and 8 • before calibration to 0.1 dB and 1.7 • after calibration.Index Terms-code-modulated embedded test, CoMET, codemodulated interferometry, phased array, built-in self-test, calibration, phase shifter.

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A 10-GHz Code-Modulated Interferometric Imager Using Commercial-Off-The-Shelf Phased Arrays

Cited by 6 publications

References 8 publications

National Radio Dynamic Zone Concept with Autonomous Aerial and Ground Spectrum Sensors

National Radio Dynamic Zone Concept with Autonomous Aerial and Ground Spectrum Sensors

PhD Thesis on Code Modulated Interferometric Imaging System using Phased Arrays

Code-Modulated Embedded Test and Calibration of Phased-Array Transceivers

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