No abstract

This paper presents design simulation, implementation, and measurement of a miniaturized GPS/K-PCS dual-band LTCC INTRODUCTIONAs mobile-communication handsets become smaller and lighter, less space is available to place the antenna and RF devices. Recently, multilayer low-temperature co-fired ceramic (LTCC) technology has been extensively used for miniaturization of RF passive components and antennas. Therefore, the size reduction of the patch antenna for integration of different radio modules into the same piece of equipment is required, and compact internal antennas with multiband operation have become a popular topic in antenna research and investigations. There are a number of effective ways to reduce the size of patch antennas: use high-permittivity substrates [1], introduce shorting pins for the shifting of the null-voltage point at the edge of the radiating patch [2], use the planar inverted-F antenna (PIFA) for low-profile characteristic [3,4]; and a combination of these approaches. Also, the basic concept to reduce the size of a microstrip patch antenna at a given resonant frequency is to increase its electrical surface-current length by changing the radiating element's shape [5,6]. An effective method for increasing the effective surface-current path is to penetrate orthogonal slits into the boundary of the radiating patch. In this way, the excited surface-current paths are lengthened in the proposed designs, and the operating frequency is greatly lowered.In this paper, a miniaturized GPS/K-PCS dual-band LTCC chip antenna is proposed for mobile-communication handsets. The experimental results for dual-band operation, return loss, and radiation pattern are presented. PROPOSED ANTENNA DESIGNThe compact meander-type antenna for dual-band operation is realized in a multilayer printed LTCC-body structure. Figure 1 shows the geometry of the proposed stacked meander-type dualband antenna mounted FR4 substrate. The dimension of LTCC chip antenna is 9 ϫ 15 ϫ 1.2 mm and the dielectric constant of the LTCC-body ceramic for antenna implementation is 7.8. The meander-type radiating patch for dual-band operation is realized by using via holes with 0.3-mm height to connect the upper-and lower-layer antennas. The dimension of the FR-4 circuit board is 40 ϫ 80 ϫ 0.8 mm and the size of the ground plane is 60 ϫ 40 mm. A 50⍀ microstrip line is used to feed the compact chip antenna, and the ground plane on the other side of the substrate is cut at the end of the microstrip feed. After a thorough parametric study of the proposed model, the optimum design parameters for the dual-band chip antenna are selected. A description of the design parameters is given in the legend of Figure 1. EXPERIMENTAL RESULTS AND DISCUSSIONIn the single-meander radiating structure, the electric fields on the each pair of the symmetrical segments in the x-direction are opposite; hence, they produce little radiation in the desired direction. On the other hand, the electric fields on the segments in the y-direction of the meander antenna ha...

This paper presents the design simulation, implementation, and measurement of a miniaturized GPS/K-PCS/ISM (2.4-GHz) triple-band LTCC meander-chip antenna for mobile-communication handsets. The dimensions of the LTCC chip antenna is 8.6 ϫ 15 ϫ 1.5 mm. In this paper, the bottom meander radiating patch is tuned to the GPS-band, the middle meander antenna with via-hole connection contributes to the K-PCS-band operation and the top radiating patch is tuned to the ISM-band (2.4 GHz INTRODUCTIONIn recent years, with technological advances, the features for a multiband antenna operation and size reduction of the radiating elements are required. Also, low-temperature co-fired ceramics (LTCC) technology has been extensively used for integration of RF active/passive components and antenna fields. In addition, flexibility in realizing easy-to-integrate circuit components such as thick film, SMT components, or chip devices has been demonstrated with LTCC technologies [1].There are a number of effective ways to reduce the size of patch antennas: use high-permittivity substrates [2], introduce shorting pins for the shifting of the null-voltage point at the edge of the radiating patch [3], use the planar inverted-F antenna (PIFA) for low-profile characteristic [4,5], changing the radiating element's current paths [6,7], and a combination of these approaches.In this paper, a miniaturized GPS/K-PCS/ISM (2.45-GHz) triple-band LTCC chip antenna with three meander-type radiating elements embedded on the LTCC-body substrate is proposed for mobile-communication handsets. The experimental results for triple-band operation, return loss, and radiation pattern are presented. ANTENNA STRUCTURE AND EXPERIMENTAL RESULTSThe basic concept to reduce the size of a microstrip patch antenna at a given resonant frequency is to increase its electrical surfacecurrent length by changing radiating element's shape. An effective method for increasing the effective surface-current path is to cut orthogonal slits into the boundary of radiating patch. In this way, the excited surface-current paths are lengthened in the proposed designs, and the operating frequency is greatly lowered. Figure 1 shows the geometry of the stacked LTCC meanderchip antenna mounted on FR4 substrate. The dimensions of LTCC chip antenna are 8.6 ϫ 15 ϫ 1.5 mm and the dielectric constant of the LTCC-body ceramic (Dupont DP 9599) for antenna implementation is 7.8. The meander-type radiating patch for triple-band operation is realized by using a via hole ( ϭ 0.5 mm) with 0.2-mm height and a via wall with 0.6-mm height to connect the middle and top radiating elements. The dimensions of the FR-4 circuit board are 40 ϫ 80 ϫ 0.8 mm and the size of the ground plane is 60 ϫ 40 mm. A 50⍀ microstrip line is used to feed the compact meander-chip antenna; the ground plane on the other side of the substrate is cut at the end of the microstrip feed.After a through parametric study of the proposed model, the optimum design parameters for the triple-band chip antenna are In this paper, the...

No abstract

Glassy dynamics of the incommensurate-commensurate phase transition in Zr 0.98 Hf 0.02 TiO 4 ceramics J. Appl. Phys. 85, 6434 (1999); 10.1063/1.369822 Electric field-temperature phase diagram of Zr 0.98 Sn 0.02 TiO 4An x-ray study of electric fields on the incommensurate phase transition in ZrTiO 4 ceramic was performed in order to obtain information concerning the nature of the competing forces that give rise to structural instability at a general wave vector. It was found that an increase in dc electric field increases the normal incommensurate phase transition temperature ͓(dT i /dE i )Хϩ1.7°C cm/kV͔. The electric field dependence of the incommensurate to commensurate transition was also investigated ͓(dT c /dE c )Хϩ1.5°C cm/kV͔.