Noyan Kinayman

Ultra-wideband radar sensors for short-range vehicular applications

The recent approval granted by the Federal Communications Commission (FCC) for the use of ultra-wideband signals for vehicular radar applications has provided a gateway for the introduction of these sensors in the commercial arena as early as 2004. However, the rules governing the allowable spectral occupancy create significant constraints on the sensors operation. This is further complicated by the variety of applications that these sensors are being required to fulfill. A review of the motivation for the development of these sensors is followed by a discussion of the consequent implications for waveform design and limitations on system architecture. Other practical considerations such as available semiconductor technology, packaging, and assembly techniques are reviewed, and results are presented for conventional surface-mount plastic packages illustrating their usefulness in the greater than 20-GHz frequency range. Suitable antenna technology for wide-band transmission is presented that is compliant with the specific restrictions stipulated in the FCC ruling. Finally, all of these considerations are combined with the presentation of a compatible integrated-circuit-based transceiver architecture. Measured results are presented for several critical circuit components including a +12-dBm driver amplifier for the transmitter, an RF pulse generator that can produce sub-1-ns pulses at a carrier frequency of 24 GHz, and a single-chip homodyne in-phase/quadrature down-conversion receiver that has a cascaded noise figure of less than 7 dB. All circuit components are fabricated in SiGe.

A fully integrated 24 GHz SiGe receiver chip in a low-cost QFN plastic package

A fully integrated, plastic packaged, 24 GHz SiGe receiver chip is presented. The chip has been manufactured using a commercially available SiGe foundry process. It can be used in a variety of applications including automotive radar sensors and phased-array receivers. The receiver supports two channels which can be used to support sum and delta antenna pattern inputs. The receiver comprises of two LNAs, a DPST switch, an I/Q downconverter, baseband variable gain amplifiers, and integrate-and-dump filters. The receiver has 45 dB of conversion gain with 7.8 dB noise figure (with plastic package) at 24 GHz

A novel microstrip mode to waveguide mode transformer and its applications

A microstrip-to-rectangular waveguide mode transformer that can be implemented using PCB technology is presented. The RT/Duroid based transformer has a wide simulated frequency response extending from 55 GHz to 140 GHz with about 0.15 dB radiation losses, Many important applications that are easy-to-manufacture are possible. Measurement results of a typical configuration are presented.

Design of 24 GHz SiGe HBT balanced power amplifier for system-on-a-chip ultra-wideband applications

The design of a balanced, three-stage, common-emitter, 24 GHz SiGe HBT power amplifier for ultra-wideband applications is described. The unique features of the amplifier are very flat gain response in the frequency band of interest and sharp gain drop outside of the band, which are important considerations for a system-on-a-chip UWB application. The amplifier has 18 dB nominal gain in the frequency band of 24/spl plusmn/2 GHz. The gain variation is /spl plusmn/0.5 dB in the same frequency band. Saturated output power is 12 dBm at 24 GHz.

A low-loss high-isolation absorptive GaAs SPDT PIN switch for 24 GHz automotive applications

Design of a low-loss high-isolation absorptive GaAs SPDT PIN diode switch at 24 GHz is presented. The switch incorporates a total of 6 PIN diodes, i.e., 3 diodes in each arm. Two of the diodes are for high isolation purposes and the third diode provides the matched load to the isolated port. The measured insertion loss and isolation are better than 1.4 dB and 47 dB, respectively, in the frequency band 22 to 26 GHz. The input and output return losses are better than 12 dB in the same frequency band

An Efficient Full-Wave Simulation Algorithm for Multiple Vertical Conductors in Printed Circuits

An efficient and rigorous numerical method, based on the spatial-domain method of moments (MoM) in conjunction with the closed-form Greens functions, is devised for the analysis of multiple vertical conductors in printed circuits. As this combination has already proven to be very efficient for the analysis of printed structures with horizontal and vertical conductors, it is extended to efficiently handle multiple vertical conductors. Some circuits with multiple vertical strips are analyzed using the proposed method, and results are compared either to those presented in the literature or to those obtained from the commercial software em by SONNET Software, North Syracuse, NY. Computational efficiency of the algorithm is assessed in terms of CPU time, and it is observed that the computational cost of the proposed algorithm is an order of magnitude less than that of the straightforward implementation of the underlaying method of the algorithm-the spatial-domain MOM using closed-form Greens functions

A novel surface-mountable millimeter-wave bandpass filter

A novel millimeter-wave waveguide bandpass filter structure suitable for surface mounting is introduced. The filter is constructed using a rectangular waveguide formed in MMIC substrate employing recently introduced microstrip-to-waveguide transducer. Input and output of the filter are implemented as microstrip lines. The transitions between the microstrip lines and the rectangular waveguide are implemented by using the microstrip-to-waveguide transition. The waveguide filter structure is surface-mountable as flip-chip and can be manufactured using a MMIC process that makes it extremely accurate. It has potential applications in millimeter-wave systems like local multipoint distribution system (LMDS) and autonomous cruise control (ACC) radar for automobiles.

Multimode TRL and LRL calibrated measurements of differential devices

A multimode TRL (MTRL) calibration technique is discussed to characterize broadband differential devices. This algorithm has the advantage of using ground-signal-signal-ground (G-S-S-G) probes in the measurements without the frequency limitations of some other 4-port algorithms due to the coupling between the signal lines. Calibration standards and the issues associated with them are described. Practical issues of the underlying theory, such as assigning the calculated eigenvalues to the correct mode and to the propagation direction, have also been addressed and one case-specific solution is suggested. Also an MTRL algorithm has been adopted to avoid some of the difficulties of calibration structures with MTRL. Odd mode test results of differential active circuits with MTRL using G-S-S-G probes are shown to be consistent with the two port test results of the same devices using S-G probes.

Low-loss high-isolation 60-80 GHz GaAs SPST PIN switch

A low-loss high-isolation GaAs SPST PIN diode switch for millimeter wave applications is presented. Modeling of PIN diode switches using full-wave electromagnetic simulators by including the semiconductor properties of the diode mesa layers is explained. This approach eliminates the necessity of model extraction from measurements in most cases. In addition, usage of simulation tools allows the optimization of diode structure for minimum insertion loss. Main loss mechanisms of GaAs PIN diodes at mm-wave frequencies are explained. Measurement results of a newly developed CPW SPST 55-85 GHz GaAs PIN switch are presented and compared with simulations. The developed shunt switch has 0.6 dB insertion loss and 20 dB return loss in the off state (through) at 75 GHz. It has 20 dB insertion loss and 1 dB return loss in the on state (isolation) at the same frequency.

Si Based UWB Radar Sensors

Automotive short-range sensor networks at 24 GHz represent the first truly high volume commercial system at mm-wave, with first year production quantities already eclipsing previous products such as autonomous cruise control (ACC), and the various microwave radio networks (e.g. LMDS). The emphasis on product quality, reliability, cost, and performance demanded by automotive OEMs has meant that an innovative approach to product development, packaging, and test has had to be introduced to mm-wave products. This paper will highlight some of the key technical hurdles and their solutions in the development and introduction to production of a 24 GHz UWB radar sensor based on custom-designed SiGe ICs.