摘要:
A multiband antenna includes at least two resonators that are driven directly and resonate in different frequency bands and a parasitically coupled resonator that resonates in one of the frequency bands. The coupled resonator is grounded with a conductive trace at one end and is thus not directly fed by the RF feed of the antenna. The coupled resonator increases the efficiency bandwidth near the frequency of operation for the coupled resonator. The antenna is fabricated from a stamped metal that is bent around or overmolded by a spacer layer. A clip formed integrally with the antenna by bending a portion of the ground plane permits attachment to the metal shield of the display of a laptop computer and is thus grounded along its length.
摘要:
An embodiment of the present invention provides an apparatus, comprising an input port and a dynamic impedance matching network capable of determining a mismatch at the input port and dynamically changing the RF match by using at least one matching element that includes at least one voltage tunable dielectric capacitor. The matching network may be a “Pi”, a “T”, or “ladder” type network and the apparatus may further comprise at least one directional coupler capable of signal collection by sampling a portion of an incident signal, a reflected signal or both. In an embodiment of the present invention, the apparatus may also include a control and power control & logic unit (PC LU) to convert input analog signals into digital signals and sensing VSWR phase and magnitude and processing the digital signals using an algorithm to give it a voltage value and wherein the voltage values may be compared to values coming from the coupler and once compared and matched, the values may be passed to a Hi Voltage Application Specific Integrated Circuit (HV ASIC) to transfer and distribute compensatory voltages to the matching network elements. Additional embodiments are disclosed.
摘要:
Apparatus for suppressing noise and electromagnetic coupling in the printed circuit board of an electronic device includes an upper conductive plate and an array of conductive coplanar patches positioned a distance t2 from the upper conductive plate. The distance t2 is chosen to optimize capacitance between the conductive coplanar patches and the upper conductive plate for suppression of noise or electromagnetic coupling. The apparatus further includes a lower conductive plate a distance t1 from the array of conductive coplanar patches and conductive rods extending from respective patches to the lower conductive plate.
摘要:
A hybrid electromagnetic bandgap (EBG) structure for broadband suppression of noise on printed wiring boards includes an array of coplanar patches interconnected into a grid by series inductances, and a corresponding array of shunt LC networks connecting the coplanar patches to a second conductive plane. This combination of series inductances and shunt resonant vias lowers the cutoff frequency for the fundamental stopband. The series inductances and shunt capacitances may be implemented using surface mount component technology, or printed traces. Patches may also be interconnected by coplanar coupled transmission lines. The even and odd mode impedances of the coupled lines may be increased by forming slots in the second conductive plane disposed opposite to the transmission line, lowering the cutoff frequency and increasing the bandwidth of the fundamental stopband. Coplanar EBG structures may be integrated into power distribution networks of printed wiring boards for broadband suppression of electromagnetic noise.
摘要:
A method, system, and apparatus for reading RFID tags in a stack of objects is described. For example, a pallet may hold a stack of objects, with one or more of the objects coupled to a RFID tag. A RFID reader may be used to read the tags in the stack. However, tagged objects in the middle of the stack may be difficult to read due to the RF signal loss passing through objects in the stack. A waveguide may be used to guide radio waves to locations in the pallet stack. For example, the waveguide can replace a slipsheet that is conventionally placed between horizontal layers of cases in the pallet stack.
摘要:
A magnetically-loaded artificial magnetic conductor surface provides enhanced bandwidth. The structure includes in one embodiment a thumbtack structure with a spacer layer that is loaded with a barium-cobalt hexaferrite based artificial magnetic material. Specifically, the geometry consists of a ground plane covered with thinly sliced ferrite tiles that are metallized and stacked. Each tile has a metal via running through its center that is electrically connected to the plated metallized surfaces. A foam spacer layer resides above the ferrite tiles. Atop the foam spacer layer rests a capacitive surface, which can be realized as a single layer array of metal patches, a multiple layer array of overlapping patches or other planar capacitive geometry.
摘要:
An embodiment of the present invention an apparatus, comprising an apparatus, comprising an adaptively-tuned antenna including a variable reactance network connected to the antenna, an RF field probe located near the antenna, an RF detector to sense voltage from the field probe, a controller that monitors the RF voltage and supplies control signals to a driver circuit and wherein the driver circuit converts the control signals to bias signals for the variable reactance network.
摘要:
An embodiment of the present invention an apparatus, comprising an adaptive impedance matching module (AIMM) adapted to minimize the magnitude of an input reflection coefficient seen at an RFin port under boundary conditions of a variable load impedance ZL, a tuner connected to the AIMM and including a plurality of variable reactance networks with independent control signals, wherein node voltages are sampled within the tuner; and a microcontroller or digital signal processor (DSP) calculates complex reflection coefficient information from the sampled voltages, the microcontroller or DSP providing a coarse and fine tune function that feeds bias signals to control impedance matching.
摘要:
Apparatus for suppressing noise and electromagnetic coupling in the printed circuit board of an electronic device includes an upper conductive plate and an array of conductive coplanar patches positioned a distance t2 from the upper conductive plate. The distance t2 is chosen to optimize capacitance between the conductive coplanar patches and the upper conductive plate for suppression of noise or electromagnetic coupling. The apparatus further includes a lower conductive plate a distance t1 from the array of conductive coplanar patches and conductive rods extending from respective patches to the lower conductive plate.
摘要:
A printed circuit board (PCB) uses arrays of chip capacitors over the entire surface of the PCB. The PCB includes an upper conductive surface routing signals to components of the PCB, a lower conductive surface, vias between the upper and lower surfaces, and a layer of patches disposed between the upper and lower surfaces to which the vias and chip capacitors are connected. The chip capacitors connect the vias to the upper conductive surface. The use of chip capacitors in a periodic lattice extends the frequency range for suppressing noise in power planes of isolated capacitors from several hundred MHz or less to 4 GHz. Combining the capacitors along with the buried patches extends the low frequency cutoff of high frequency reference noise suppression circuits to 50 MHz or less.