Antenna Switch

Antenna switch. (Courtesy of Sorep-Erulec. EhiPont Application Note Reference H-84342.) 

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Figure 1.23 and Figure 1.24 are examples of modules designed for use in the 900-MHz to 2.4-GHz range. New commercial wireless applications of ceramic technology continue to emerge for RF front-end modules, filters, antenna switches, and radio modules. 

This module (Figure 1.24) is an antenna switch/filter module designed for dual-band portable wireless telephones. It combines GSM/DCS/PCS diplex-ing and receiving/transmitting antenna functions. The 8.9 x 9.9 mm (0.35 x 0.39 in.) LTCC module uses a 26-pad EGA format. In addition to the surface-mounted passive components, the six-conductor-layer structure incorporates 13 embedded capacitors and inductors to form the diplexer and 2 low-pass filters. 

Magennis et al. prepared two azacrown ether derivatives 53 and 54, which formed 1 1 complexes with Eu " and Tb " cations [134]. Addition of pi-colinate anion to a solution of Eu -53 or Tb -53 gave 250- or 170-fold enhancement in the emission signals. Eu -54 exhibited similar augmentations upon the addition of picolinate anion (120-fold). Since these crown ethers were non-chromophoric, the coordinated aromatic carboxylate guests worked as antennae switching on the lanthanide luminescence. 

Keywords Molecular Devices a Molecular Machines a Molecular Wires a Antenna Systems a Molecular Switches a Plug/socket Systems a Pseudorotaxanes a Rotaxanes a Catenanes a Supramolecuiar Chemistry a Photochemistry a Electrochemistry a Luminescence... 

The DNA hybridization of an Au NP-DNA hybrid can be controlled through inductive coupling of a radiofrequency (1 GHz) electromagnetic field to the Au NP (1.4 nm), which acts as an antenna, increasing the local temperature of the bound DNA and inducing denaturation. The switch on-off of the electromagnetic field induces a reversible denaturation-rehybridization of the DNA double-helix [196]. 

The Eu(III) and Tb(III) complexes of 36, developed by Parker et al., showed modulation of the lanthanide emission caused by changes in pH [139]. The coordinating antenna was covalently attached to the complex but only coordinates to the metal centre under specific pH conditions. This was demonstrated on a cyclen complex where three carboxylate pendant arms were attached, allowing coordination to take place, and resulted in the formation of a charge-neutral complex. The fourth position contained an aromatic sulfonamide tethered via an ethyl carbon chain, 36a-36c. Studies showed that luminescence was switched on when the complexes were in alkaline conditions because the two metal-bound waters (q = 2) were displaced. This led to a situation where the pendant aryl sulfonamide groups were coordinated... 

The technique was made practical for personnel screening applications by incorporating sequentially switched linear antenna arrays to improve the data collection speed to near real-time rates [ 17,27-31 ]. The linear arrays allowed one axis of the two-dimensional planar aperture to be scanned electronically at very high speed (on the order of several microseconds per element). This reduced total data collection for practical systems to human body is not transparent to millimeter-waves, personnel will need to be inspected from multiple aspects (front and back at a minimum). 

The wideband holographic imaging technique is very sensitive because of the active, coherent, heterodyne detection that is employed in typical systems [15-17], Therefore, the primary limitation on image acquisition is the time required to mechanically scan the transceiver. Two-dimensional raster scans are often used for laboratory experiments, and these typically require scan times on the order of 1-30 min. Practical systems employing linear switched antenna arrays and mechanical scanning reduce this time to 1-10 seconds [15-17],... 

A cylindrical prototype was developed at PNNL that operates from 27-33 GHz using a vertically oriented linear array, as shown in Fig. 9. This system uses switching and transceiver technology similar to the prototype shown in Fig. 4. However, this system is composed of 384 antenna elements versus 128 for the previous system. This system collects a 360° scan in 6-10s. Image reconstruction is then performed using a conventional PC coupled to an array of high-speed co-processors. Example cylindrical images collected with a laboratory transceiver and scanner are shown in the lower half... 

Fig. 9.17 Range of soft ferrite components (i) TV scanning yoke (components kindly supplied by Philips Components Ltd.) (ii) UR core and TV line output transformer (iii) E core for switched mode power supply (iv) wide band transformer core (v) core giving good magnetic shielding (vi) high Q (adjustable) filter core (cf. Fig. 9.48) (vii) precision ferrite antenna for transponder (viii) multilayer EMI suppressors (ix) toroids for laser and radar pulse applications (x) typical EMI shields for cables, ((ii)—(x) Courtesy of Ferroxcube UK .)...

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