A Scalable Four-Channel Frequency-Division Multiplexing MIMO Radar Utilizing Single-Sideband Delta-Sigma Modulation

A scalable four-channel multiple-input multiple-output (MIMO) radar that features a modular system architecture and a novel frequency-division multiplexing approach is presented in this article. It includes a single 30-GHz voltage-controlled oscillator (VCO) for the local oscillator signal generation, four cascaded 120-GHz transceivers with a frequency quadrupler, and on-board differential series-fed patch antennas. The utilized uniform antenna configuration results in 16 virtual array elements and enables an angular resolution of 6.2°. The vector modulators in the transmit (TX) paths allow the application of complex bit streams of second-order delta-sigma modulators easily generated on a field-programmable gate array (FPGA) to implement single-sideband (SSB) modulation on the TX signals resulting in orthogonal waveforms for the MIMO operation. Only one phase-locked loop and no digital-To-Analog converter is required. The waveform diversity also allows the simultaneous transmission of the TX signals to reduce the measurement time. The application of the SSB modulation on the frequency-modulated continuous-wave MIMO radar requires only half of the intermediate frequency bandwidth compared with the double-sideband modulation. The issue of the phase and amplitude mismatches at the virtual array elements due to the scalable radar architecture is addressed and a calibration solution is introduced in this article. Radar measurements using different numbers of virtual array elements were compared and the digital-beamforming method was applied to the results to create 2-D images. © 1963-2012 IEEE

Investigation Of Effective Medium Theory Concerning Applications For Skin Cancer Detection

Skin cancer detection proves to be complicated and highly dependent on the examiner’s skills. Millimeter-wave technologies seem to be a promising aid for the detection of skin cancer. The different water content of the skin area affected by cancer compared to healthy skin changes its reflective property. Due to limited available resources on the dielectric properties of skin cancer, especially in comparison to surrounding healthy skin, accurate simulations and evaluations are quite challenging. Therefore, comparing different results for different approaches and starting points can be difficult. In this paper, the Effective Medium Theory is applied to model skin cancer, which provides permittivity values dependent on the water content

Spur canceling technique by folded XOR gate phase detector and its application to a millimeter-wave SiGe BiCMOS PLL

A folded XOR gate (FXOR) phase detector (PD) is proposed for millimeter-wave (mmW) SiGe integer- $N$ phase-locked loops (PLLs) to relax the tradeoff between PLL loop bandwidth and reference spur rejection. With four current-reuse XOR gates jointly participated in phase detection, the reference spur generated by each XOR gate neutralizes that generated from its complementary counterpart, without degrading the phase margin or incurring extra power. The high gain of the FXOR PD suppresses its noise contribution, and the PD inherently enables frequency tracking together with lock detection. Fabricated in a 130-nm SiGe BiCMOS process, the 80-GHz mmW PLL demonstrates a -73-dBc reference spur, a minimum integrated jitter of 79.5 fsrms (10 kHz-100 MHz), and a figure of merit (FoM) of-241 dB

Wideband Frequency Quadrupler for D-Band Applications in BiCMOS Technology

This paper presents the design of a D-band frequency quadrupler (FQ) based on two cascaded frequency doublers. Each doubler relies on the bootstrapped Gilbert cell (GC) mixers. The FQ is developed with a standard 130-nm SiGe BiCMOS process. It consists of fully integrated input and output baluns, frequency doublers, and matching networks. The design of the FQ was optimized via single-ended matching networks to reduce the chip area and increase bandwidth. The results based on the EM-simulation of FQ with the assistance of the hicum model for the transistor, demonstrate a peak conversion gain and output power of 25 dB and 5 dBm, respectively at 130 GHz. The FQ shows a 3-dB bandwidth higher than 84 GHz with an n th harmonic rejection of at least 16 dBc. The FQ can be exploited in various systems design for different D-band applications. The future work includes measurement of the FQ

D-Band Balanced PA with Wideband Performance in BiCMOS Technology

This paper presents the design of a balanced power amplifier (PA) using a 130-nm SiGe BiCMOS process. The PA consists of three stages, each based on cascode topology. The design of the PA was optimized using low-Q matching networks for the D-band applications. The results based on EM-simulation of the PA, with assistance of vbic and hicum models for the transistor, demonstrate an average peak gain of 26.5 dB with the 3-dB bandwidth higher than 80 GHz. In terms of large-signal, the PA provides an output power and PAE larger than 14 dBm, and 4 percent, respectively, in the D-band. Moreover, it provides an output power greater than 13 dBm at 110–190 GHz. The PA is highly suitable to drive frequency multipliers for the development of broadband sub-THz signal sources. The future work includes measurement of the PA

220-360-GHz Broadband Frequency Multiplier Chains (x8) in 130-nm BiCMOS Technology

This article presents two broadband frequency multiplier chains (FMCs) fabricated with a standard 130-nm SiGe BiCMOS process. In both solutions, a broadband push-push frequency doubler (x2) operating at 220–360 GHz was employed. In order to properly drive such a doubler, with sufficient input power and bandwidth, two different power amplifiers (PAs) have been adopted: the former is based on a cascode configuration and the latter is based on a stacked topology. In addition, a D-band frequency quadrupler (x4) has been integrated before the PAs and doubler, to complete the design of frequency eighth tupler (x8) chains. The first FMC with the cascode PA achieves peak output power of 2.3 dBm, with maximum conversion gain (G C ) and bandwidth of 15 dB and 127 GHz, respectively. The second FMC with the stacked PA delivers a saturated output power of 2.5 dBm, with a maximum G C and a bandwidth of 12 dB and 72 GHz, respectively. The two FMCs consume maximum dc power of 0.537 and 0.542 W. The complete design procedure of the FMCs is presented in this article. To the best of our knowledge, the reported bandwidth is state-of-the-art and widest among SiGe based FMCs

High Performance Asymmetric Coupled Line Balun at Sub-THz Frequency

In this paper, we report a high-performance balun with characteristics suitable for future broadband sub-THz differential circuits. The idea of the balun is based on three asymmetric coupled lines, which enhance the odd mode capacitances to equalize the even/odd mode phase velocities. The inner line of the three asymmetric coupled lines is configured to form the open stub ( λ /2), while the outer lines form short stubs ( λ /4). To further reduce the phase imbalance, the short stubs in one of the arms of the balun are connected with vias and a lower metal layer. The balun is developed using the standard 130-nm SiGe BiCMOSback-end process and EM simulated with ADS momentum and Sonnet. The −10-dB reflection coefficient (S 11 ) bandwidth of the balun is 136 GHz (88−224 GHz). It shows insertion loss (including RF pads) <1.5 dB, phase imbalance <7 degrees, and amplitude imbalance <1 dB at 94−177 GHz. Furthermore, a scaled-down version of the balun operates on the WR-6, WR-5, and WR-4 frequency bands without significant degradation in its performance. Such characteristics of the balun make it an ideal candidate for various broadband differential circuits

Using Effective Medium Theory to Simulate Skin Cancer Detection with a Substrate-Integrated Waveguide Probe

A method for evaluating skin cancer detection based on millimeter-wave technologies is presented. For this purpose, the relative permittivities are calculated using the effective medium theory for the benign and cancerous lesion, considering the change in water content between them. These calculated relative permittivities are further used for the simulation and evaluation of skin cancer detection using a substrate-integrated waveguide probe. A difference in the simulated scattering parameters S 11 of up to 13dB between healthy and cancerous skin can be determined in the best-case