Ultra wideband (uwb) baby monitors for detection of infant cardiopulmonary distress

Abstract

Ultra wideband patient monitoring systems, and particularly baby monitoring systems, adapted to prevent reflective loss between the antenna and the patient's body. The devices, systems and methods described herein may be used to efficiently couple UWB energy to a patient for patient monitoring. In particular, described herein are impedance transformer pads, mats and the like, upon which a patient may comfortably lie while being monitored via one or more UWB sensors (e.g., antenna); the impedance transformer pads help match the impedance and prevent reflective loss of UWB energy. Also described herein are bassinets, including NICU bassinets and baby monitors.

What is claimed is: 
     
         1 . An impedance transformer pad for use with an ultra wideband (UWB) monitoring system to minimize reflective loss of the UWB energy, the impedance transformer pad comprising:
 a soft or resilient recumbent surface formed at least in part from an impedance transformer region having a thickness of between about 0.4 cm and 7 cm, wherein the impedance transformer region has at least one layer having a dielectric constant of between about 5 and about 20; and   a UWB antenna abutting the impedance transformer region;   wherein the UWB antenna is configured to transmit and receive UWB signals through the impedance transformer region to monitor the patient resting on the pad.   
     
     
         2 . The pad of  claim 1 , wherein the recumbent surface is sized to fit into a bassinet. 
     
     
         3 . The pad of  claim 1 , wherein the impedance transformer region has a single homogenous layer. 
     
     
         4 . The pad of  claim 1 , wherein the impedance transformer region has at least two adjacent planar layers, wherein each planar layer has a different thickness and dielectric constant. 
     
     
         5 . The pad of  claim 1 , wherein the impedance transformer region has three adjacent planar layers, wherein each planar layer has a different thickness and dielectric constant. 
     
     
         6 . The pad of  claim 1  wherein the impedance transformer region is formed of silicone. 
     
     
         7 . The pad of  claim 1 , wherein the impedance transformer region has a thickness of between about 0.5 cm and 5 cm. 
     
     
         8 . The pad of  claim 1 , further comprising a backing beneath the impedance transformer region and the UWB antenna. 
     
     
         9 . The pad of  claim 1 , further comprising a plurality of UWB antennas beneath and abutting the impedance transformer region. 
     
     
         10 . The pad of  claim 1 , wherein the antenna is configured to emit a UWB signal having a bandwidth, and wherein the impedance transformer region has one or more planar layers each having a dielectric and wherein and the thickness of each layer is approximately one quarter or one half of the wavelength of the center frequency of the bandwidth in the dielectric of that layer. 
     
     
         11 . A ultra wideband (UWB) patient monitoring system having an impedance transformer pad to minimize reflective loss, the system having a UWB bandwidth for emitting sensing signals, the system further comprising:
 an impedance transformer pad having a UWB antenna beneath an impedance transformer region, the antenna configured to transmit UWB signals through the impedance transformer region to a patient resting on the pad,   wherein the impedance transformer region has one or more planar layers and the thickness of each layer is approximately one quarter or one half of the wavelength of the center frequency of the bandwidth in the dielectric of that layer; and   a processor configured to receive signals from UWB antenna to monitor the patient.   
     
     
         12 . The system of  claim 11 , wherein the impedance transformer pad further comprises a backing layer behind the impedance transformer layer and the antenna. 
     
     
         13 . The system of  claim 11 , further comprising a cable connecting the antenna of the impedance transformer pad to the processor. 
     
     
         14 . The system of  claim 11 , wherein the impedance transformer pad is flexible, hypoallergenic, and water proof. 
     
     
         15 . The system of  claim 11 , wherein the impedance transformer region of the impedance transformer pad has a single homogenous layer configured as a quarter wavelength layer wherein the thickness is approximately one quarter of the wavelength of the center frequency of the bandwidth in the dielectric of the layer. 
     
     
         16 . The system of  claim 11 , wherein the impedance transformer region of the impedance transformer pad has two or more layers. 
     
     
         17 . The system of  claim 11 , wherein the impedance transformer region of the impedance transformer pad has three layers, comprising adjacent planar layers configured as a quarter wavelength layer, a half wavelength layer, and a quarter wavelength layer. 
     
     
         18 . The system of  claim 11 , wherein the impedance transformer is configured to fit within a bassinet. 
     
     
         19 . The system of  claim 11 , wherein the impedance transformer pad comprises a plurality of UWB antennas. 
     
     
         20 . The system of  claim 11 , wherein the UWB antenna is an air antenna. 
     
     
         21 . A method of monitoring an infant using an ultra wideband (UWB) radar system including an impedance transformer pad, the method comprising:
 placing the infant atop the impedance transformer pad; and   emitting a UWB signal from a UWB antenna, wherein the signal passes from the antenna, through an impedance transformer region of the impedance transformer pad and into the infant, further wherein the impedance transformer region has at least one layer having a dielectric constant of between about 5 and about 20,   wherein the impedance transformer pad reduces the impedance miss-match between the antenna and the infant to reduce reflective loss of energy from the signal.   
     
     
         22 . The method of  claim 21 , further comprising receiving a reflected UWB signal from the infant using the UWB antenna. 
     
     
         23 . The method of  claim 21 , wherein emitting the UWB signal comprises passing the signal through the impedance transformer region wherein the impedance transformer region has a single homogenous planar layer having a dielectric that is the geometric mean of the dielectric of the antenna and the dielectric of the infant. 
     
     
         24 . The method of  claim 21 , wherein emitting the UWB signal comprises passing the signal through the impedance transformer region wherein the impedance transformer region has a thickness between about 0.4 cm and about 7 cm. 
     
     
         25 . The method of  claim 21 , wherein emitting the UWB signal comprises passing the signal through the impedance transformer region wherein the impedance transformer region has a plurality of layers each with a dielectric value, wherein the thickness of each layer is approximately one quarter or one half of the wavelength of a center frequency of the bandwidth of the emitted signal in the dielectric of that layer. 
     
     
         26 . The method of  claim 21 , wherein placing comprises placing the infant atop the impedance transformer pad within an NICU bassinet. 
     
     
         27 . The method of  claim 21 , wherein emitting comprises emitting the UWB signal from the antenna to the infant through the impedance transformer region without passing thought the air. 
     
     
         28 . An ultra wideband (UWB) baby monitoring system, the system comprising:
 an impedance transformer pad having a soft or resilient recumbent surface upon which a baby may rest;   a UWB antenna coupled to the impedance transformer pad and configured to emit a UWB signal through the transformer pad and into the baby, wherein the impedance transformer pad is configured to prevent reflective loss of more than 50% of energy of the UWB signal; and   a processor in communication with the UWB antenna and configured to monitor the baby when the baby is resting on the impedance transformer pad.   
     
     
         29 . The system of  claim 28  configured to apply UWB signals in a bandwidth having a center frequency, wherein the impedance transformer pad comprises an impedance transformer region forming the recumbent surface, the impedance transformer region having one or more planar layers each with a different dielectric value. 
     
     
         30 . The system of  claim 28  configured to apply UWB signals in a bandwidth having a center frequency, wherein the impedance transformer pad comprises an impedance transformer region forming the recumbent surface, the impedance transformer region having one or more planar layers each with a dielectric value, wherein the thickness of each layer is less than one half of the wavelength of the center frequency in the dielectric of that layer. 
     
     
         31 . The system of  claim 28  configured to apply UWB signals in a bandwidth having a center frequency, wherein the impedance transformer pad comprises an impedance transformer region forming the recumbent surface, the impedance transformer region having one or more planar layers each with a dielectric value, wherein the thickness of each layer is approximately one quarter or one half of the wavelength of the center frequency in the dielectric of that layer. 
     
     
         32 . The system of  claim 28 , wherein the impedance transformer pad is configured to fit within a bassinet. 
     
     
         33 . The system of  claim 28 , wherein the impedance transformer pad comprises a non-toxic, hypoallergenic, and water proof material. 
     
     
         34 . A bassinet configured for ultra wideband (UWB) monitoring of an infant, the bassinet comprising:
 a temperature-regulated bassinet enclosure having walls and a lower surface; and   at least one UWB antenna integrated into the bassinet and configured to emit UWB energy into an infant within the bassinet from the tower surface of the bassinet;   wherein the tower surface of the bassinet impedance matches to minimize reflective loss of UWB energy between the UWB antenna and the infant.   
     
     
         35 . The bassinet of  claim 34 , wherein the lower surface comprises an impedance transformer pad covering the UWB antenna on that the UWB antenna emits UWB signals through the impedance transformer pad. 
     
     
         36 . The bassinet of  claim 34 , wherein the UWB antenna is configured to apply UWB signals in a bandwidth having a center frequency, further wherein the lower surface comprises an impedance transformer region covering the UWB antenna, on which an infant may rest, wherein the impedance transformer region has one or more planar layers each with a dielectric value, wherein the thickness of each layer is less than one half of the wavelength of the center frequency in the dielectric of that layer. 
     
     
         37 . The bassinet of  claim 34 , wherein the UWB antenna has a dielectric approximately matched to the dielectric of the infant. 
     
     
         38 . The bassinet of  claim 34 , wherein the UWB antenna has a dielectric of approximately 50. 
     
     
         39 . The bassinet of  claim 34 , wherein further comprising a plurality of UWB antennas. 
     
     
         40 . The bassinet of  claim 34 , further comprising a processor configured to receive signals from the UWB antenna to monitor the infant.