Abstract: Disclosed are a single-frequency circular polarization positioning antenna and a wearable device. The single-frequency circular polarization positioning antenna includes an inverted F antenna and a parasitic antenna which are in an orthogonal layout; resonance is generated on the parasitic antenna through a coupling effect by means of feeding the inverted F antenna, so that the overall structure of the circular polarization antenna is simplified, and is achieved on a wearable product more easily. Therefore, the positioning antenna can better receive signals of a navigation satellite, and right hand circular polarization radiation generated by an annular radiating body can also filter left hand circular polarization navigation satellite signals reflected by high buildings or the ground, so as to reduce the multipath interference, thus effectively improving the positioning accuracy of the positioning antenna of the wearable device.

Abstract: Various illustrative aspects are directed to a data storage device comprising a disk; a read/write head having read and write portions configured to read data from and write data to the disk; read and write heaters configured to thermally adjust read and write spacings of the read and write portions from the disk surface; and a controller configured to control power applied to the read and write heaters based on a dual heater power ratio (DHR) of the respective power applied to each heater. The DHR is set based on a point during touchdown at which a reader shield and a writer shield have maximum contact with the surface of the disk (DHRmax).

Abstract: Various illustrative aspects are directed to a data storage device comprising a disk; a read/write head having read and write portions configured to read data from and write data to the disk; read and write heaters configured to thermally adjust read and write spacings of the read and write portions from the disk surface; and a controller configured to control power applied to the read and write heaters based on a dual heater power ratio (DHR) of the respective power applied to each heater. The DHR is set based on a point during touchdown at which a reader shield and a writer shield have maximum contact with the surface of the disk (DHRmax).

Abstract: A multipath suppression method based on a steepest descent method includes stripping, according to carrier Doppler shift information fed back by a phase-locked loop, a carrier from an intermediate-frequency signal input into a tracking loop; constructing, on the basis of the autocorrelation characteristics of a ranging code, a quadratic cost function related to a measurement deviation of the ranging code, the cost function being not affected by a multipath signal; and finally, designing a new tracking loop of the ranging code according to the quadratic cost function and the principle of the steepest descent method, such that the loop has a multipath suppression function without increasing the computational burden. Compared with a narrow-distance correlation method, the current method reduces computing resources by ?, the design and adjustment of parameters are simple and feasible, a multipath suppression effect is superior, and a high engineering application value is obtained.

Abstract: A multipath suppression method based on a steepest descent method includes stripping, according to carrier Doppler shift information fed back by a phase-locked loop, a carrier from an intermediate-frequency signal input into a tracking loop; constructing, on the basis of the autocorrelation characteristics of a ranging code, a quadratic cost function related to a measurement deviation of the ranging code, the cost function being not affected by a multipath signal; and finally, designing a new tracking loop of the ranging code according to the quadratic cost function and the principle of the steepest descent method, such that the loop has a multipath suppression function without increasing the computational burden. Compared with a narrow-distance correlation method, the current method reduces computing resources by ?, the design and adjustment of parameters are simple and feasible, a multipath suppression effect is superior, and a high engineering application value is obtained.

Abstract: A PMR, TAMR or MAMR (Perpendicular Magnetic Recording, Thermally Assisted Magnetic Recording or Microwave Assisted Magnetic Recording) slider-mounted read/write head produces less heat during operation by using magnetic read shields in which are embedded a patterned layer of thermally absorbing material. At least one shield includes a heating coil which is used to adjust the fly-height of the slider by creating a thermal protrusion at the slider ABS. When additional sources of energy, such as laser heating, microwave heating or the write coil itself, are applied to the recording medium, the shields can overheat, adversely affecting their performance. The patterned layer of heat absorbing material reduces the flow of heat from the thermal heating coil to the air bearing surface (ABS) thus cooling the region around the write head while not adversely affecting the shape of the thermal protrusion.

Abstract: A Perpendicular Magnetic Recording (PMR) head is configured for use in Thermally Assisted Magnetic Recording (TAMR). Two or three contiguous write shields, of various widths and thicknesses, formed on a leading edge side of the write gap (WG), main pole (MP) and near-field transducer (NFT), protect the head during write touchdowns (TD) and signal the approach of such a touchdown. Moreover during a write touchdown the contact with the head is restricted to the large write shields, producing a large touchdown area (TDA) and insuring the lifetime of the head.

Abstract: A method of operating an HDD having a slider-mounted read/write head that is configured for dynamic fly-height operation (DFH) and includes at least one head-disk interference sensor (HDIs). By operating the DFH to lower the head and subjecting the HDIs signal to a power-law enhancement, a consistent and accurate determination of the touchdown power (TDP) can be obtained. Combining absolute TDP determination with a method for measuring relative changes of FH, an absolute determination of FH can be determined.

Abstract: A method of operating a HDD having a read/write head configured for Perpendicular Magnetic Recording (PMR) and configured for use in Thermally Assisted Magnetic Recording (TAMR). By using selected settings of a power ratio (PR) value to ensure that accurate fly height (FH) measurements of head-disk interference (HDI) can be taken during write touchdowns (TDs), head damage can be eliminated during HDI events. Under normal operating conditions the PMR head develops a sharp protrusion due to heating from the TAMR apparatus as well as the write current and read and write heaters. The sharp protrusion is prone to striking the disk surface, instead of the shields doing so. The shields would be more capable of absorbing the HDI, which would allow the HDI sensors (HDIs) to provide a more sensitive reading of the HDI which would prevent head wear caused by the sharp protrusion.

Abstract: A PMR read/write head configured for thermally assisted recording (TAMR) includes thermally active bumper pads formed to each side of a write element to provide enhanced touchdown (TD) protection to the write head element where it emerges adjacent to the plasmon near-field spot produced by the TAMR apparatus. The bumper pads are disposed about the write head and absorb heat energy generated by active heating elements, the write current and the energy generated by the TAMR apparatus. Absorption of this energy causes the bumper pads to expand and protrude outward from the slider ABS to protect the read/write head from both intentional and unanticipated touchdown events. The PMR read/write head is then mounted on a slider and the assembly is incorporated into a hard disk drive (HDD).

Abstract: A slider design for a hard disk drive (HDD) features an air-bearing surface (ABS) topography with soft bumper pads (SBP) formed proximally to corners of the leading edge and the trailing edge. The bumper pads are formed by a process that combines the use of a first photomask for subtractive etching of the ABS to form pedestals, followed by additive depositions onto the pedestals using a second lift-off photomask. The additive process deposits sequences of Si layers and diamond-like carbon (DLC) layers to produce a soft bumper pad that is energy absorbing and heat conducting, thereby protecting the recording media from surface damage and thermal erasures.

Abstract: A connector assembly (100,500) includes a plate (101,501) having a body (107,507) and one or more legs (108,109,110,508,509,510) extending distally from the body. The body can define an aperture (112,512). A flexible substrate (102,502) can electrically couple to the legs such that a portion (202,602) of the body extends distally from an edge (203,603) of the flexible substrate. A connector (103,503) is electrically coupled to the flexible substrate, with one or more circuit components (104,105,504,505) electrically coupled between the legs and the connector. The flexible substrate can define a perimeter (201,601) that is complementary in shape to an upper surface (122,522) of a busbar connector (106,506).

Abstract: Dynamic fly height (DFH) controlled read/write heads using multiple heaters have their heater powers set within a range of ratios that allows minimum clearances to be set between the read-gap and the write-gap and the surface of a disk, thereby providing improved touch-down detection. Determining the correct range of power ratios requires varying the ratio to create an adjustable protrusion profile for the read and write elements in the head and measuring values of the ratio and corresponding values of read gap and write gap clearances that create points of minimum clearance. By adjusting the ratio of power supplied to the heaters, different protrusion profiles can be produced, clearance control for sigma reduction can be obtained and read/write readiness and operation consistency and reliability can be improved.

Abstract: A photoluminescent material has the characteristic of a long photoluminescence decay and has the general composition Ca3-x-m-nAxSc2-yMySi3-zEzO12:mCe3+,nMn2+, where A is at least one divalent cation including Sr, Ba or a combination of monovalent and trivalent cations including combinations of Li, Na, K, B, Al and Ga; M is at least one trivalent cation including Al, Ga, or a divalent cation including Mg, E is a combination of a trivalent and a pentavalent cation including B, Al, Ga, N and P, or a combination of monovalent and trivalent cations including Li, Na, K, B, Al, Ga, N and P. The A cation replaces Ca; the M cation replaces Sc, and E replaces Si. This Mn and Ce doped phosphor emits in the yellow to green with a peak at around 510 and/or 560 and 690 nm. The phosphor material has applications in LED illumination systems.

Abstract: Chlorosilicate-based phosphors configured to emit yellow-green light in a wavelength ranging from about 500 nm to about 560 nm in response to an excitation source emitting at about 400 nm to about 480 nm, wherein the light emitted by the phosphor has a decay time ranging from about 1 millisecond (1 ms) to about 10 milliseconds (10 ms). The phosphor comprises a compound of the family Ca8-x-yAxEuyMg1-m-nBmMnn(Si1-sCsO4)4R2, where A is at least one divalent cation including Ca, Sr, Ba; B is Zn or Cd, or a divalent metal ion other than an alkaline earth; C is a cation, including at least one of Ge, Al, B, Gd, Ga, and N, and R is an anion, including F, Cl, Br, I, all respectively either individually, or in combinations.

Abstract: Methods are provided for determining the heater power level of a dynamic flying height (DFH) type write head at which a touch down (TD) occurs. Each method makes use of the DC component of a head-disk interference (HDI) sensor and the determination of the TD heater energy is deduced from certain characteristics of the function relating heater power to HDI DC signal strength. Characteristics that provide reliable indication of a TD include points of minimum slope, structure of the slope's slope and the properties of a linear fit to the slope if the slope does not converge to a consistent value. It is found that the use of all methods in combination allow a reliable TD determination under virtually all conditions.

Abstract: A method to compensate for spacing variations between a dynamic fly height (DFH) controlled read/write head and a rotating disk surface. Using a HDI sensor or equivalent indicator of touchdowns, a power profile is calculated for an arbitrary track on a disk. The profile tracks disk topography by recording touchdown power at each of a series of sectors into which the track is subdivided. The resulting power profile, smoothed and expressed as a function of sector position, substitutes for the usual constant TD power setting that provides only an uncompensated range of spacing variations. A fixed back-off spacing power is added to the power profile enabling the head to fly over the track at a constant spacing. The power profile can be calculated to account for various temperature and pressure conditions.

Abstract: A method for determining the surface distortions of a disk in a spin-stand or single or multiple disk hard disk drive (HDD) utilizing a DFH type write head. A stepwise power curve is supplied to the DFH head, the head is flown over a chosen track on the disk, and the high frequency signal from a HDI sensor is analyzed in order to determine the step of an initial touchdown power and the step of a complete touchdown power as a function of individual sectors in a sector subdivision along a chosen track. The HDI sensor signal is averaged within each step of the power curve between these two steps and a Ratio variable, Ratio=(Max. amplitude)/(RMS amplitude) is calculated for each step and is averaged over each rotation of the disk during the step.

Abstract: Embodiments of the present invention include a head slider for a magnetic disk drive. The head slider comprises a first recess on the air bearing surface of the head slider. The head slider further comprises a second recess on the air bearing surface, wherein the first recess is deeper than the second recess and is closer to the leading edge than the second recess and wherein the second recess is closer to the trailing edge than the first recess.

Abstract: A method to compensate for spacing variations between a dynamic fly height (DFH) controlled read/write head and a rotating disk surface. Using a HDI sensor or equivalent indicator of touchdowns, a power profile is calculated for an arbitrary track on a disk. The profile tracks disk topography by recording touchdown power at each of a series of sectors into which the track is subdivided. The resulting power profile, smoothed and expressed as a function of sector position, substitutes for the usual constant TD power setting that provides only an uncompensated range of spacing variations. A fixed back-off spacing power is added to the power profile enabling the head to fly over the track at a constant spacing. The power profile can be calculated to account for various temperature and pressure conditions.