Planar dielectric resonator stabilized HEMT oscillator integrated with CPW/aperture coupled patch antenna

A new design of an active antenna with a dielectric resonator stabilized high electron mobility transistor (HEMT) oscillator (DRO) and an aperture-coupled patch antenna is reported. The circuit is fabricated using coplanar waveguide (CPW) with the oscillator and the antenna on opposite sides of the substrate. The active antenna was demonstrated at 7.6 GHz; however, the design can be scaled to higher frequencies. Excellent oscillator characteristics and radiation patterns were obtained

Sandia Pueblo: Persistence and Change in a New Mexican Indian Community

The dissertation has a twofold purpose: to redress the lacuna in the social anthropological literature with respect to the Tiwa-speaking pueblo of Sandia, New Mexico, and to account for the persistence of this traditionally oriented community despite dependence upon a complex industrial society which is potentially conducive to sociocultural disorganization. To accomplish this dual aim, field work was conducted at Sandia for two and one-half years, during which observations were made of contemporary pueblo social relations and lengthy interviews were conducted with selected residents

Healthy children\u27s response to chronic illness in siblings.

This nation\u27s number one health problem for both children and adults is chronic illness (Travis, 1976). This is especially tragic in the case of children, seven to ten percent of whom are afflicted with one or more serious chronic illnesses of physical origins (Mattson, 1972; Travis, 1976). This figure represents an increase in recent years, in part because medical advances have changed many once fatal childhood illnesses to more longterm, chronic conditions. Moreover, due to improved methods of early diagnosis and treatment, more families are now living with chronically ill children, and for longer periods of time. Long term illness in a child is a significant stress on the family members: they must cope with the physical, financial, and psychological hardships of living with a very ill child (Drotar, 1978). For progressive illnesses, the family must watch the sick child slowly decline in health. Even if the child lives a relatively normal life span (with impaired physical functioning), the family may have to continually readjust to periods of acute exacerbations alternating with remissions (Mattson, 1972)

Microwave characterization of slotline on high resistivity silicon for antenna feed network

Conventional silicon wafers have low resistivity and consequently unacceptably high value of dielectric attenuation constant. Microwave circuits for phased array antenna systems fabricated on these wafers therefore have low efficiency. By choosing a silicon substrate with sufficiently high resistivity it is possible to make the dielectric attenuation constant of the interconnecting microwave transmission lines approach those of GaAs or InP. In order for this to be possible, the transmission lines must be characterized. In this presentation, the effective dielectric constant (epsilon sub eff) and attenuation constant (alpha) of a slotline on high resistivity (5000 to 10 000 ohm-cm) silicon wafer will be discussed. The epsilon sub eff and alpha are determined from the measured resonant frequencies and the corresponding insertion loss of a slotline ring resonator. The results for slotline will be compared with microstrip line and coplanar waveguide

Linearly tapered slot antenna impedance characteristics

The paper presents for the first time an experimental technique to de-embed the input impedance of a LTSA from the measured reflection coefficient. The results show that the input impedance is dependent on the semi-flare angle and the length of the LTSA. The Re(Z(sub in)) is large when the electrical length of the LTSA is small and is on the order of few thousand ohms. However for an electrically large LTSA the Re(Z(sub in)) is in the range of 55 to 130 ohms. These results have potential applications in the design of broad band impedance matching networks for LTSA

Linearly Tapered Slot Antenna Radiation Characteristics at Millimeter-Wave Frequencies

An endfire travelling wave antenna, such as, a linearly tapered slot antenna (LTSA) is a viable alternative to a patch antenna at millimeter-wave frequencies because of its simple design and ease of fabrication. This paper presents the radiation characteristics of LTSA at higher millimeter-wave frequencies. The measured radiation patterns are observed to be well behaved and symmetric with the main beam in the endfire direction. The measured gain is about 10 dB. The LTSAs have potential wireless applications at 50 GHz, 77 GHz, and 94 GHz

Linearly tapered slot antenna with dielectric superstrate

The effect of dielectric superstrate on a linearly tapered slot antenna (LTSA) was investigated experimentally. It was observed that the dielectric superstrate improves the directivity but generally at the expense of higher sidelobe level. The dielectric superstrate could be used to reduce the physical length and to improve the radiation characteristics of the LTSA