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 . 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 having a plurality of adjacent planar layers wherein each layer has a dielectric, and wherein 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   emitting a UWB signal from a UWB antenna beneath the impedance transformer pad, 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 is arranged so that the dielectric constants of the adjacent planar layers increase towards the infant and are 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.   
     
     
         2 . The method of  claim 1 , further comprising receiving a reflected UWB signal from the infant using the UWB antenna. 
     
     
         3 . The method of  claim 1 , 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. 
     
     
         4 . The method of  claim 1 , 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. 
     
     
         5 . The method of  claim 1 , wherein placing comprises placing the infant atop the impedance transformer pad within an NICU bassinet. 
     
     
         6 . The method of  claim 1 , wherein emitting comprises emitting the UWB signal from the antenna to the infant through the impedance transformer region without passing thought the air. 
     
     
         7 . 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 having a plurality of adjacent planar layers wherein each layer has a dielectric; and   emitting a UWB signal from a UWB antenna beneath the impedance transformer pad, 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 is arranged so that the dielectric constants of the adjacent planar layers increase towards the infant and are 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.   
     
     
         8 . The method of  claim 7 , further comprising receiving a reflected UWB signal from the infant using the UWB antenna. 
     
     
         9 . The method of  claim 7 , 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. 
     
     
         10 . The method of  claim 7 , 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. 
     
     
         11 . The method of  claim 7 , wherein placing comprises placing the infant atop the impedance transformer pad within an NICU bassinet. 
     
     
         12 . The method of  claim 7 , wherein emitting comprises emitting the UWB signal from the antenna to the infant through the impedance transformer region without passing thought the air. 
     
     
         13 . 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 having a plurality of adjacent planar layers wherein each layer has a dielectric, and wherein 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   emitting a UWB signal from a UWB antenna beneath the impedance transformer pad, wherein the signal passes from the antenna, through an impedance transformer region of the impedance transformer pad and into the infant, further wherein the dielectric constants of the planar layers are between about 5 and about 20, and 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.   
     
     
         14 . The method of  claim 13 , further comprising receiving a reflected UWB signal from the infant using the UWB antenna. 
     
     
         15 . The method of  claim 13 , 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. 
     
     
         16 . The method of  claim 13 , 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. 
     
     
         17 . The method of  claim 13 , wherein placing comprises placing the infant atop the impedance transformer pad within an NICU bassinet. 
     
     
         18 . The method of  claim 13 , wherein emitting comprises emitting the UWB signal from the antenna to the infant through the impedance transformer region without passing thought the air.