The E-mail Address es you entered is are not in a valid format.
- ISBN 13: 9780890067550.
- Crucial Conversations: Tools for Talking When Stakes Are High.
- Z/p-equivariant maps between lens spaces and spheres.
- Jump Start Sass.
Please re-enter recipient e-mail address es. You may send this item to up to five recipients. The name field is required. Please enter your name. The E-mail message field is required.
Please enter the message. Please verify that you are not a robot. Would you also like to submit a review for this item? You already recently rated this item. Your rating has been recorded. Write a review Rate this item: 1 2 3 4 5. Preview this item Preview this item. Series: Artech House antenna library. Allow this favorite library to be seen by others Keep this favorite library private. Find a copy in the library Finding libraries that hold this item Reviews User-contributed reviews Add a review and share your thoughts with other readers.
She serves on the IEEE standards committees for She earned her B.
See All Customer Reviews. Shop Textbooks. The antennas can be integrated with RF chips using either the on-package , or the on-chip [7,8] or even the on-wafer  technique. The Figure 2 illustrates for few cases, the respective concept behind the integration technique. The SIP technology was invented by Philips Corporation, on which the microdevices are flip-chip mounted onto passive component substrates, whose consequence is the footprint area minimization as well as the parasitic elements.
A lateral cut photograph is showed in order to better illustrate this integration concept . To resume, in the on-package integration the antenna is coupled into the package where the RF chip is supported and is the simplest technique. The on-chip integration requires more than one integration process for more than one technology, which can lead to a situation where the technology for fabricating the RF chip can be incompatible with the one used for fabricating the antenna.
The Photographs in the Figure 2 b shows microsystems where the antennas were directly fabricated within the microdevice [7,8]. This second technique presents more advantages when compared with the on-package: both the microdevice and antenna are simultaneously subjected to the same process steps during the fabrication because they share the same set of technological rules followed by the microelectronic foundries.
This make easy to overcome impedance mismatching problems and at the same time results on cheaper solutions because no additional step processes and external connections on PCBs are not required. Moreover, it is possible to obtain more compact and smaller devices than with other techniques. However, the main drawback of this technique is not allowing antennas whose sizes are far outside of the order of magnitude of microdevices. Moreover, a new antenna either with a new shape or new specifications implies the project redraw and a new submission to the foundry for fabricating the new microdevice.
Finally, the technique that seems to be promising is the on-wafer because wafer-level-packaging WLP techniques for joining heterogeneous technologies are offered by the industry with a relatively low-price.
The Figure 2 c helps to understand the WLP technique, e. In this picture, it is easy to identify few microsystem microfabrication techniques: a starting with the coplanar waveguide fed aperture CPWFA and benzocyclobutene BCB sealing ring previously patterned; b bonding step to join the antenna into the substrate containing the microelectronics ; c substrate thinning step; d glass dicing.
The photograph on left part of the Figure 2 c shows few prototypes of fabricated antennas suspended in the cavity of the packaging . This last technique is especially suitable for integrating patch-antennas due to their planar shape with RF chips . A variety of antennas with a variety of shapes and physical placement are related in the literature, as it is the work done by Soontornpipit et al  who fabricated implantable patch antennas with spiral and serpentine shapes.
The folded shorted-patch antenna in the Figure 3 a was fabricated by Mendes  and it exploits the third dimension for fabricating small antennas with relatively good radiation characteristics. As illustrated in the Figure 3 b , specific microfabrication techniques were employed on its fabrication: e. Finally, the research group of Chow et al  explores an outstanding methodology that makes profit of cardiovascular stents to receive RF signals inside the human body. The averaged parameters help to obtain the skin-depth and the path-loss characteristics of the propagation medium.
However, the simple consideration of path-loss is not simpler because as stated by Scanlon et al , the electrical parameters of the surrounding tissue around the RF receiver and the body's structure have a strong influence in the radiation pattern of the receiving antenna. The main consequences of this are difficulties due to fading caused by radiation pattern fragmentation especially observed in the azimuthal plane. This happen because the human body is composed by a variety of tissues comprising the skin, fat, muscle, bone, nerve, among others.
Therefore, it is required to do an averaging of the several electric parameters. Nevertheless and independently of the electrical parameters that are used, the following skin-depth equation can be used for obtaining an estimative of the expected path-loss :. The quantity f GHz is the RF frequency expressed in giga-cycles per second. This difficulty can also be used in a positive way, as it happened with the work done by Karacolak et al  for continously measuring the itens of glucose the variations of the electric parameters are used for measuring the sugar concentration.
9 editions of this work
The previous parameters were used for obtaining the skin-depth for MHz, 2. This means that for high frequencies, the path-loss can't be the only criterion to follow. In the studies carried out by Siwiak , the muscle tissue of the human body was modeled as a lossy wire antenna for simulating its interaction with radiowaves. More precisely, the human body were modeled as a cylinder of saline water with frequency dependeny electrical parameters.
These studies resulted in skin-depths of approximately 60 mm and 26 mm for MHz and 2. Measurement and data acquisition systems. The Figure 4 shows a block diagram of a generic measurement instrument. The blocks of a measurement system can be grouped into three major types: the real world representing the physical quantity to be acquired , the interface block with the sensor and the core e. There are situations where the interface block can be part of the core, e. In this context, it must be clarified that a sensor can't be confused with a transducer, because the later can perform the same function of the former but if the former is passive for example, a physical quantity dependant resistor mounted in a Whitestone bridge then additional circuits must be provided for obtaining the signal from the sensor.
This means that the set composed by sensor and powering system makes a transducer, confirming that certain sensors are simultaneously transducers. The core blocks can include electronics of acquisition. The core also provides signal processing functions for signal conditioning purposes. These last functions include amplification with the possibility to adjust the gain , filtering either low pass or band pass or even high pass filtering and analog to digital conversion.
Then, the user can read the acquired values in a dedicated display. A more sophisticated core system can interface with the external world either to connect several measurement instruments or to send data to a central unit for further processing. The core blocks of the measurement instruments can be analog or digital. The analog is the less versatile core because requires the presence of a person to annotate the measurements. This type of instrument is very limited and very difficult to be adapted to wide disparities of signals to measure.
Furthermore, it is not possible to send wirelessly the physical quantities, unless a specific interface with an analog modulation scheme is provided. A digital core can be used for connecting transducers whose output can provide signals in the analog or in the digital domain. The difference from their analog counterparts resides on the conversion component used in the final processing stage, e. The inclusion of multiplexers enables the acquisition of multiple channels with a single measurement instrument.
This topic will be focus of discussion in the next section. Then and after the ADC conversion, the acquired measurements can be presented in a numerical display. These cores can also be built with internal memory for storing the ADC converted samples for rendering in a more complete displaying system e. Finally and thanks to the latest developments of microelectronics, by making available transducers with digital outputs for example, integrated monolithic temperature transducers , Hall's effect magnetometers  and accelerometers , among others it is possible to have full-digital and reusable cores.
The judicious selection of transducers and cores can be decisive points for fabricating wireless instruments with low-power, reduced sizes and low-prices. A wireless instrument communicates with the external world by radio-frequency RF.
Thus, a wireless interface must be provided for allowing RF communications. The Figure 5 shows a generic schematic block of a wireless microsystem doing functions of a stand-along wireless instrument. These microsystems are composed by transducers, electronics for control and signal processing, by memory and by a RF interface the RF transceiver for connecting to an associated antenna.
The dimensions of the RF transceiver must be comparable with others elements integrated in the microsystem e. The miniaturization of electronics and the spreading of fabrication processes for integrating heterogeneous technologies e.
ISBN 13: 9780890067550
All these issues combined with the flexibility to select which and the number of transducers for integrating together with the RF transceiver and remain electronics allows engineers to design wide number of devices for wide number of applications. This last goal can be easily achieved with multi-chip-module MCM techniques applied to a limited number of components which can be of different technologies. In conclusion, the technology is also a major point to allow the fabrication of wireless microsystems for use in wireless instruments.
In this section, few examples for each of the ISM band in the Figure 1 are presented for a better view of wireless instruments potential. The selected architecture explores the super-regeneration phenomena to achieve a high sensitivity.