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This article presents the development of a focal plane array (FPA) for terahertz imaging applications with a near diffraction-limited resolution achieved through a very tight sampling of the focal plane. The antenna array is integrated with direct detectors in a 22-nm CMOS technology and operates from 200 to 600 GHz. The tight sampling of the focal plane is realized by using a combination of leaky-wave radiation and a dual-polarized connected array configuration that closely resembles a chessboard. By utilizing both the polarizations in the chessboard design, the number of array elements per unit area is effectively doubled. The geometry of the chessboard array was co-optimized together with that of a silicon elliptical lens to achieve both high aperture efficiency and beam overlap. Measurements in the WR2.2 band of a fabricated demonstrator showed that an aperture efficiency of −4.1 dB was realized at 400 GHz. The average gain roll-off between two diagonally adjacent array elements was measured to be −1.5 dB at 400 GHz. Compared to the reference configuration of an idealized, equivalently sampled hexagonal FPA, the improvement in gain at the edge of coverage yields 1.2 dB, which includes 1.9 dB of ohmic losses in the chessboard array. The agreement between measurements and simulations proved to be within 1 dB from 325 to 475 GHz., Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Tera-Hertz Sensing, Electronics

In this contribution we will present the diffraction-limited imaging capabilities of a focal plane array (FPA) of antenna-coupled direct-detectors at submillimeter wavelengths. The FPA prototype is a tightly sampled, 12-pixel array that was developed in a 22 nm CMOS technology and it covers a band from 200 GHz to 600 GHz. A quasi-optical (QO) setup was developed to actively illuminate this FPA in order to perform imaging with > 40 dB SNR. The resulting images will be the first that have diffraction-limited angular resolution at these wavelengths, which demonstrates that this FPA design can be very attractive for future passive THz imaging applications., Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Tera-Hertz Sensing, Electronics

A complete system modeling and characterization of a wideband differential terahertz (THz) direct detector, integrated in a commercial CMOS technology, is presented. The detector consists of a recently developed double leaky-slot lens antenna that operates from 200 to 600 GHz in combination with a differential Schottky barrier diode (SBD) direct detection circuit. The proposed methodology, starting from low-frequency measurements on a standalone SBD, is able to adequately model the spectral radiometric performance. The system noise-equivalent power (NEP) is characterized from 325 to 500 GHz in excellent agreement with the proposed system model. The measured NEP, 20 pW/√Hz minimum and 90 pW/√Hz frequency averaged, is compromised with respect to the average NEP of 2.7 pW/√Hz that was initially predicted by simulations using the process design kit (PDK) model, since the available SBDs are operating beyond their cutoff frequency. The diodes and models provided by the PDK proved to be inaccurate in predicting circuit behavior at these high frequencies. By using the proposed analysis and modeling approaches, an accurate wideband antenna–detector codesign could be applied for future passive THz imaging applications based on CMOS technologies., Accepted author manuscript, Tera-Hertz Sensing, Electronics

A complete system modeling and characterization of a wideband differential terahertz (THz) direct detector, integrated in a commercial CMOS technology, is presented. The detector consists of a recently developed double leaky-slot lens antenna that operates from 200 to 600 GHz in combination with a differential Schottky barrier diode (SBD) direct detection circuit. The proposed methodology, starting from low-frequency measurements on a standalone SBD, is able to adequately model the spectral radiometric performance. The system noise-equivalent power (NEP) is characterized from 325 to 500 GHz in excellent agreement with the proposed system model. The measured NEP, 20 pW/√Hz minimum and 90 pW/√Hz frequency averaged, is compromised with respect to the average NEP of 2.7 pW/√Hz that was initially predicted by simulations using the process design kit (PDK) model, since the available SBDs are operating beyond their cutoff frequency. The diodes and models provided by the PDK proved to be inaccurate in predicting circuit behavior at these high frequencies. By using the proposed analysis and modeling approaches, an accurate wideband antenna–detector codesign could be applied for future passive THz imaging applications based on CMOS technologies., Accepted author manuscript, Tera-Hertz Sensing, Electronics

A 12-pixel THz Focal Plane Array (FPA), integrated in Global Foundries 22nm CMOS technology, enabling high resolution passive THz imaging, is presented. The array efficiently couples blackbody radiation from 200 GHz to 600 GHz to Schottky Barrier Diodes (SBDs) in a differential topology. An antenna-detector co-design results in an average Noise Equivalent Power (NEP) of 0.9 pW/ sqrt{ text{Hz}}. An extremely small array periodicity is achieved by using two orthogonal polarizations. Such configuration enables passive imaging with a near-diffraction limited resolution while simultaneously maintaining a high optical efficiency of 42%. The array is currently in tape-out and measurements will be presented at the conference., Tera-Hertz Sensing, Electronics

A 12-pixel THz Focal Plane Array (FPA), integrated in Global Foundries 22nm CMOS technology, enabling high resolution passive THz imaging, is presented. The array efficiently couples blackbody radiation from 200 GHz to 600 GHz to Schottky Barrier Diodes (SBDs) in a differential topology. An antenna-detector co-design results in an average Noise Equivalent Power (NEP) of 0.9 pW/ sqrt{ text{Hz}}. An extremely small array periodicity is achieved by using two orthogonal polarizations. Such configuration enables passive imaging with a near-diffraction limited resolution while simultaneously maintaining a high optical efficiency of 42%. The array is currently in tape-out and measurements will be presented at the conference., Tera-Hertz Sensing, Electronics

The optical performance of a wideband double bowtie slot antenna, implemented in 28nm CMOS technology, is evaluated. The antenna serves as a verification antenna for an uncooled single-pixel radiometer operating from 200 GHz to 600 GHz. The performance is evaluated in terms of radiometric pattern that is derived from the measured radiation patterns and simulated optical efficiency., Tera-Hertz Sensing, Electronics

The optical performance of a wideband double bowtie slot antenna, implemented in 28nm CMOS technology, is evaluated. The antenna serves as a verification antenna for an uncooled single-pixel radiometer operating from 200 GHz to 600 GHz. The performance is evaluated in terms of radiometric pattern that is derived from the measured radiation patterns and simulated optical efficiency., Tera-Hertz Sensing, Electronics

The design and performance analysis are presented for a passive uncooled radiometer pixel suitable for integration in 28 nm CMOS technology. In the configuration a single wideband antenna, operating from 200 GHz to 600 GHz, is connected to a pn-junction diode. Including the antenna-detector impedance mismatch, the detector shows an average NEP of 2.71 pW/√Hz such that, together with the antenna, the radiometer promises fully passive and uncooled imaging capabilities with 2.6 K temperature sensitivity at a 10 Hz refresh rate. The design is planned for fabrication and measurement., Accepted Author Manuscript, Tera-Hertz Sensing, Electronics

The design and performance analysis are presented for a passive uncooled radiometer pixel suitable for integration in 28 nm CMOS technology. In the configuration a single wideband antenna, operating from 200 GHz to 600 GHz, is connected to a pn-junction diode. Including the antenna-detector impedance mismatch, the detector shows an average NEP of 2.71 pW/√Hz such that, together with the antenna, the radiometer promises fully passive and uncooled imaging capabilities with 2.6 K temperature sensitivity at a 10 Hz refresh rate. The design is planned for fabrication and measurement., Accepted Author Manuscript, Tera-Hertz Sensing, Electronics

To accommodate the growing demand for wireless communications, new techniques are required to increase throughput of wireless networks. One technology aiming to increase the spectral efficiency of wireless devices is full duplex (FD) radios. These systems are capable of single carrier transmission and reception and could ideally double the spectral efficiency of future wireless systems. To make such systems a commercial reality, self-interference cancellation (SIC) techniques are required to suppress transmitter leakage into the receiver. This work investigates the level of SIC an integrated hybrid transformer can provide to make FD a reality. This work also includes an investigation in the SIC capabilities of an integrated hybrid transformer operating with a commercially available planar inverted-F antenna (PIFA) and presents the design and evaluation of a prototype in UMC 180nm RFCMOS. The prototype consists of a transformer, a tunable impedance and a LNA. Measurement results on this prototype showed isolation peaks of 80 dB, with an isolation band width of 1 MHz for 60 dB isolation and a Tx insertion loss, measured gain and NF of 3.5 dB, 5dB and 9dB, respectively, while providing a IIP3 of 0dBm at the LNA output and a common-mode Tx isolation at the input of the LNA of 20 dB. The measurements also showed that the duplexer can be made self-tunable by using search algorithms that converge within 150 measurements. The relation between isolation and impedance resolution is derived and proven to be 6dB every time the absolute difference between the impedances at both sides of the transformer is halved., Microelectronics & Computer Engineering, Electrical Engineering, Mathematics and Computer Science

To accommodate the growing demand for wireless communications, new techniques are required to increase throughput of wireless networks. One technology aiming to increase the spectral efficiency of wireless devices is full duplex (FD) radios. These systems are capable of single carrier transmission and reception and could ideally double the spectral efficiency of future wireless systems. To make such systems a commercial reality, self-interference cancellation (SIC) techniques are required to suppress transmitter leakage into the receiver. This work investigates the level of SIC an integrated hybrid transformer can provide to make FD a reality. This work also includes an investigation in the SIC capabilities of an integrated hybrid transformer operating with a commercially available planar inverted-F antenna (PIFA) and presents the design and evaluation of a prototype in UMC 180nm RFCMOS. The prototype consists of a transformer, a tunable impedance and a LNA. Measurement results on this prototype showed isolation peaks of 80 dB, with an isolation band width of 1 MHz for 60 dB isolation and a Tx insertion loss, measured gain and NF of 3.5 dB, 5dB and 9dB, respectively, while providing a IIP3 of 0dBm at the LNA output and a common-mode Tx isolation at the input of the LNA of 20 dB. The measurements also showed that the duplexer can be made self-tunable by using search algorithms that converge within 150 measurements. The relation between isolation and impedance resolution is derived and proven to be 6dB every time the absolute difference between the impedances at both sides of the transformer is halved., Microelectronics & Computer Engineering, Electrical Engineering, Mathematics and Computer Science

This thesis describes the work done on a control system for the Transportable Atmospheric RAdar (TARA), which is located at the Cabauw Experimental Site for Atmosperic Research (CESAR). It describes the way in which this radar control unit was implemented within the TARA, by making use of a high-level programming language. The control unit consists of a PXI-system of National Instruments, LabVIEW software, a DDS from Analog Devices and provided Matlab code. The project resulted in a working prototype. The TARA itself is a FM-CW radar with the possibility of sending and receiving in multiple polarizations and orientations for weather measurements. The system was tested and most functions worked properly. During the test, the measurements with the new system generated the same data as the current system. This proved that the system is working correctly, which is of great importance for the ATMOS group, because they are planning to transport the TARA to a measurement campaign in France in 2012 using the upgraded system., Remote Sensing of the Environment, Electrical Engineering, Mathematics and Computer Science

This thesis describes the work done on a control system for the Transportable Atmospheric RAdar (TARA), which is located at the Cabauw Experimental Site for Atmosperic Research (CESAR). It describes the way in which this radar control unit was implemented within the TARA, by making use of a high-level programming language. The control unit consists of a PXI-system of National Instruments, LabVIEW software, a DDS from Analog Devices and provided Matlab code. The project resulted in a working prototype. The TARA itself is a FM-CW radar with the possibility of sending and receiving in multiple polarizations and orientations for weather measurements. The system was tested and most functions worked properly. During the test, the measurements with the new system generated the same data as the current system. This proved that the system is working correctly, which is of great importance for the ATMOS group, because they are planning to transport the TARA to a measurement campaign in France in 2012 using the upgraded system., Remote Sensing of the Environment, Electrical Engineering, Mathematics and Computer Science

This thesis describes the work done on a control system for the Transportable Atmospheric RAdar (TARA), which is located at the Cabauw Experimental Site for Atmosperic Research (CESAR). It describes the way in which this radar control unit was implemented within the TARA, by making use of a high-level programming language. The control unit consists of a PXI-system of National Instruments, LabVIEW software, a DDS from Analog Devices and provided Matlab code. The project resulted in a working prototype. The TARA itself is a FM-CW radar with the possibility of sending and receiving in multiple polarizations and orientations for weather measurements. The system was tested and most functions worked properly. During the test, the measurements with the new system generated the same data as the current system. This proved that the system is working correctly, which is of great importance for the ATMOS group, because they are planning to transport the TARA to a measurement campaign in France in 2012 using the upgraded system., Remote Sensing of the Environment, Electrical Engineering, Mathematics and Computer Science