Langis Roy

24 GHz On-Chip Antennas and Balun on Bulk Si for Air Transmission

The conditions are investigated under which standard digital bulk Si technology can yield efficient on-chip antennas and baluns for fully differential transmitter and receiver implementations. The effects of the IC material properties and the antenna geometry on radiation and impedance characteristics have been studied. 24 GHz on-chip antennas on lossy Si have been successfully demonstrated, using a standard IC fabrication compatible Cu process. The fabricated antennas demonstrate a gain ranging from 8- to - 10.5 dBi, which is to the best of the authors knowledge, the highest gain reported for antennas in a 10 Omega-cm Si substrate to date.

Wireless Dosimeter: System-on-Chip Versus System-in-Package for Biomedical and Space Applications

A new floating-gate (FG) MOSFET based wireless dosimeter system-in-package (SiP) is presented. This miniature and completely integrated wireless dosimeter SiP comprises a CMOS FG radiation sensor and transmitter (TX) in a low-temperature co-fired ceramic (LTCC) package. The design is very well suited to wireless transmission of radiation sensor data in radiotherapy and to Extra Vehicular Activity Radiation Monitoring (EVARM) in space. Two different solutions, namely system-on-chip (SoC) and SiP, are demonstrated. In the SoC, which is size and power efficient, the TX includes an on-chip loop antenna which also acts as the inductor for the VCO resonant tank circuit. The SiP solution has an LTCC antenna with optimized impedance to conjugate match the TX chip. The radiation sensor demonstrates a measured sensitivity of 5 mV/rad. The SoC module size is only 2 mm2, consumes 5.3 mW of power and delivers -0.9 dBm of radiated power, sufficient to communicate with a low noise receiver connected to an off-chip patch antenna placed 1.38 m away. The SiP design provides a larger communication range of 75 m at the cost of additional power consumption and size.

Microwave characterization of a microstrip line using a two-port ring resonator with an improved lumped-element model

A two-port ring resonator is used to characterize the microwave properties of a microstrip line printed on Ferro A6-S low-temperature co-fired ceramic. The ring and its coupling gaps are simulated using a simple lumped-element model. The coupling gaps are modeled as capacitors, the values of which are extracted using a commercial two-and-one-half-dimensional electromagnetic simulator. The validity of the lumped-element model is assessed by comparing the simulated and experimental resonant frequencies and, for the first time, the simulated magnitudes of both the reflection and transmission coefficients are also compared with those obtained experimentally. A correction for the frequency pushing due to the capacitive loading of the coupling gaps is also presented. The resulting model is then shown to predict the resonant frequencies to within 0.11% from 5 to 40 GHz. The simulated and experimental reflection magnitudes are within 0.5 dB across the band, whereas the transmission magnitudes are within 3.5 dB up to 22 GHz. Experimental results indicate that the loss of the microstrip ranges from approximately 0.11 to 0.42 dB/cm across the band and that the relative permittivity of the substrate is nearly constant versus frequency with an average value of 6.17.

Material characterization using a quasi-optical measurement system

Application of a quasi-optical apparatus in the determination of the constituent parameters of materials is presented in this paper. Correction terms are introduced to remove the errors due to the misplacement of the sample and the calibration procedure. Good agreement was observed between manufacturer specifications and measurements after application of the correction terms.

Design Enhancement of Miniature Lumped-Element LTCC Bandpass Filters

We present a novel methodology for the design of miniature lumped element components embedded in a low-temperature co-fired ceramic (LTCC) package. The entire process, from initial schematic design, through individual element design, to complete device optimization is discussed. The design and fabrication of novel miniature lumped element LTCC filters is used to validate the proposed methodology. Commercial software tools are used to accurately model and simulate all aspects of the devices to ensure design success. In addition, the filters occupy only 0.03 lambda times 0.05 lambda times 0.004 lambda of a conventional low-permittivity LTCC substrate, which is among the smallest sizes reported. An advantage of these filters is that they use a true third-order topology with three multilayer L-C resonators, leading to superior stopband performance. For the first time, measured results are shown for two new bandpass filters targeted for global positioning system applications. Measured results are in good agreement with the simulations and show an insertion loss of 2.8 dB and a return loss of 21.3 dB at the center frequency of 1.64 GHz.

Ferrite LTCC-Based Antennas for Tunable SoP Applications

For the first time, ferrite low temperature co-fired ceramic (LTCC) tunable antennas are presented. These antennas are frequency tuned by a variable magnetostatic field produced in a winding that is completely embedded inside the ferrite LTCC substrate. Embedded windings have reduced the typically required magnetic bias field for antenna tuning by over 95%. The fact that large electromagnets are not required for tuning makes ferrite LTCC with embedded bias windings an ideal platform for advanced tunable system-on-package applications. Measurements of rectangular microstrip patch antennas on a ferrite LTCC substrate display a maximum tuning range of 610 MHz near 12 GHz. Two different bias windings and their effect on the antenna performance are discussed, as is the effect of antenna orientation with respect to the bias winding. The antenna radiation patterns are measured under biased and unbiased conditions, showing a stable co-polarized linear gain.

High-Q LTCC resonators for millimeter wave applications

This paper examines millimeter wave LTCC waveguide resonators and proposes a design strategy for obtaining high-Q factors using a number of loss-reduction and feeding techniques. The modeling and simulation methodology employed has been confirmed through a baseline LTCC resonator design, showing excellent agreement between measurements and predictions. An optimum design was then carried out which yielded an unloaded Q of over 1000 at Ka-band, the highest value ever reported for a standard LTCC process.

Development of a millimeter-wave ferrite-filled antisymmetrically biased rectangular waveguide phase shifter embedded in low-temperature cofired ceramic

The theory of a new ferrite-filled rectangular waveguide phase shifter is presented, showing that the device offers more than twice the maximum phase shift of a classical dual-slab ferrite-loaded waveguide phase shifter. The complete analytical field derivation of the new phase shifter is presented. The prototype 36-GHz phase shifter has been completely embedded in an uncharacterized experimental low-temperature cofired ferrite ceramic material, essentially becoming an integral part of a chip package. The fabricated prototype is only 3.5-cm long, 5-mm wide, and 1-mm high. Preliminary measurements of the nonoptimized prototype reveal a controllable, nonreciprocal phase shift of 52.8/spl deg/ at 36 GHz for a bias current of 500 mA, and an insertion loss of approximately 3.6 dB, including transition loss. This paper marks the first time that a ferrite waveguide phase shifter has been realized as a lightweight, compact, and rugged module that can be easily mass produced at low cost. Since it is embedded in a package, the phase shifter can be readily integrated with other active and passive system components that would ideally be contained within the same package.

A Fully Differential Monolithic LNA With On-Chip Antenna for a Short Range Wireless Receiver

This letter presents the smallest reported 5 GHz receiver chip (1.3 mm2) with an on-chip antenna in standard 0.13 mum CMOS process. The miniaturization is achieved by placing the circuits inside a meandered antenna. The on-chip antenna is conjugately matched to the low noise amplifier (LNA) over a wide frequency range. The design methodology for co-design of the on-chip antenna and LNA is described. The LNA is completely differential, consumes only 8 mW of power and provides a gain of 21 dB. Design tradeoffs and measurement challenges are given.

Characterization of an experimental ferrite LTCC tape system for microwave and millimeter-wave applications

An experimental-low temperature cofired ceramic (LTCC) ferrite tape system is characterized using circuits that are fabricated from the very material under test. Such in situ circuits provide data that are thought to be more representative of the performance obtainable by more complicated circuitry that will eventually be made from the same material using the same fabrication method. Emphasis is placed on simple measurements that can be performed using a minimum amount of equipment. For the first time, a compact in situ LTCC solenoid transformer is used to measure the magnetostatic properties of the ferrite, yielding a measured saturation flux density of 230 mT, a remanence of 136 mT, and a coercivity of 688 A/m. The peak linear relative permeability of the ferrite is 97 and its Curie temperature is low, only 117/spl deg/C. A novel two-port line-connected ring resonator is used to characterize the material in the 6-40 GHz range. At frequencies above 20 GHz, the relative permittivity of the ferrite is 11.0, whereas its loss tangent ranges from 0.002 to 0.004, demonstrating the ferrites suitability for use in microwave and millimeter-wave circuitry.