Abstract:
A passively re-radiating cell phone sleeve assembly capable of receiving a nested cell phone provides signal boosting capabilities and provides a radar enablement. Signal boosting is enabled by use of an additional antenna, a pass-through repeater, dual antenna isolation capability and other features.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/US2012/056708, filed Sep. 21, 2012, which claims the benefit of the following, the entire contents of each of which are hereby fully incorporated herein by reference for all purposes: (i) U.S. patent application Ser. No. 13/238,894, filed Sep. 21, 2011, titled “Inductively coupled signal booster for a wireless communication device and in combination therewith,” now U.S. Pat. No. 8,248,314, issued Aug. 21, 2012, and which claims priority from provisional patent application No. 61/385,386, filed Sep. 22, 2010; and (ii) U.S. patent application Ser. No. 13/590,053, filed Aug. 20, 2012, titled “Combination hand-held phone and radar system,” now U.S. Pat. No. 8,519,885, issued Aug. 27, 2013, which is a Continuation-In-Part (CIP) of U.S. application Ser. No. 13/238,894; and (iii) U.S. patent application Ser. No. 13/591,152, filed Aug. 21, 2012, titled “Smart channel selective repeater,” now U.S. Pat. No. 8,559,869, issued Oct. 15, 2013, which is a CIP of application Ser. Nos. 13/238,894 and 13/590,053; and (iv) U.S. patent application Ser. No. 13/591,171, filed Aug. 21, 2012, titled “Isolation enhancement between planar antenna elements,” now U.S. Pat. No. 8,560,029, issued Oct. 15, 2013, which is a CIP of application Ser. No. 13/238,894 filed on Sep. 21, 2011, and Ser. No. 13/590,053, filed on Aug. 21, 2012, and Ser. No. 13/591,152, filed on Aug. 21, 2012. 
    
    
     BACKGROUND 
     This disclosure relates to the field of wireless telecommunications and more particularly to a sleeve enclosure for extending the functional capability of a cell phone. Publication WO 2020/098540 discloses a double molding process wherein in a first molding step, an antenna is embedded within a resin jacket and in a second molding step the resin jacket is embedded within a device case by an insertion molding processes. Publication JP2006/148751 discloses the coupling of antennas built into a cover which when placed over the case of a portable terminal are positioned in close proximity to internal antennas of the terminal and are thereby able to be inductively coupled for strengthening transmitted signals. 
     SUMMARY 
     The present disclosure describes a sleeve capable of physically receiving and electronically communicating with a cell phone or other portable wireless communication device and also providing certain ancillary features and supports to the operation of the cell phone including: boosting the cell phone&#39;s signal reception and transmission including by use of an additional antenna, providing a radar feature whereby the cell phone is able to display a photo or video of a distant moving object while also calculating and displaying its velocity, providing a repeater capable of auto-tuning to a frequency of the cell phone and boosting signal strength, and employing dual planar antennas capable of operating in close proximity at two different frequencies with excellent isolation between the antennas, such antennas supporting the capabilities of the repeater. The sleeve increases the range of the cell phone and has integrated construction so that it is relatively inexpensive to manufacture and durable in use. The sleeve is able to combine the reception and transmission capacities of a nested cell phone&#39;s built-in antenna with an external antenna mounted on the sleeve, or a remote antenna, for greatly improved RF reception and transmission. 
     The details of one or more embodiments of these concepts are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of these concepts will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1A  is an example perspective view of the presently described sleeve; 
         FIG. 1B  is an example partial sectional side view of the sleeve taken from cutting plane  1 B- 1 B and additionally showing a portion of a nested cell phone within the sleeve; 
         FIG. 1C  is an example partial cutaway portion of the sleeve shown in  FIG. 1A  showing an additional enablement for storing an external antenna; 
         FIG. 2  is an example sectional view taken from cutting plane  2 - 2  in  FIG. 1A  showing a portion of a nested cell phone above a portion of the sleeve; 
         FIG. 3  is an example perspective view of the interior of a back panel of the sleeve showing details of a radar system&#39;s components therewithin; 
         FIG. 4  is an example front face view of a cell phone showing a radar related display; 
         FIG. 5  is an example electrical schematic diagram of the sleeve and the cell phone showing an electrical interconnection; 
         FIGS. 6A and 6B  are example sectional views taken from cutting plane  6 - 6  in  FIG. 1 ; 
         FIG. 7  is an example block diagram showing the sleeve and radar communicating with a target; 
         FIG. 8  is an example schematic diagram of the radar; 
         FIG. 9  is a logical flow diagram of an exemplary radar process; 
         FIGS. 10 ,  11 , and  12  are exemplary electrical schematic diagrams of a signal repeater circuit; 
         FIG. 13  is a logical flow diagram of an exemplary process of the repeater circuits of  FIGS. 10 ,  11 , and  12 ; 
         FIG. 14  is an example plan view of a dual antenna system with slot isolation; and 
         FIG. 15  is an example graphical plot showing isolation between antenna elements. 
     
    
    
     Like reference symbols in the various drawing figures indicate like elements. 
     DETAILED DESCRIPTION 
       FIG. 1A  illustrates a re-radiating cell phone sleeve assembly, referred to herein as “sleeve  10 ,” capable of conforming to, and nesting with, a cell phone or similar portable wireless device which is not a part of sleeve  10 . The term cell phone, referred to herein as “phone  20 ,” is used throughout this description and it should be recognized that this term may refer to a cellular telephone or any other portable RF communication apparatus and sleeve  10  may be fabricated to dimensions that will accept each different size and shape phone  20 . Sleeve  10  includes a full or partial enclosure  30  made of a conformable material such as rubber, rubberized plastic, a plastic and rubber combination, or a combination of plastic polymers. Enclosure  30  is capable of tightly fitting over and around at least a portion of phone  20 . In the preferred embodiment shown in  FIGS. 1A and 1B , enclosure  30  has a rear panel  32  integral with a surrounding side wall  34  which has an internal lip flange  36  all around. When phone  20  is nested within sleeve  10 , a lip flange  36  ( FIG. 1B ) extends peripherally over a portion of a face  22  ( FIG. 4 ) of phone  20  so as to secure phone  20  within sleeve  10 . Also, the material of which enclosure  30  is fabricated may be at least partially elastic so that it may be stretched slightly upon receiving phone  20  and thereby providing an improved securement. 
     Referring again to  FIG. 1A , a planar multi-layer radio frequency (RF) coupling probe  40  may be embedded within rear panel  32  by insertion injection molding or other means, and may be in a location that is in close proximity to, and may lay directly adjacent to an internal antenna  50  ( FIG. 2 ) of phone  20  when phone  20  is within sleeve  10 . In this manner, probe  40  is a position for electromagnetic coupling with internal antenna  50  for boosting the phone&#39;s signal strength. Inductive, capacitive or other electromagnetic coupling may be employed. 
     Referring still to  FIG. 2 , probe  40  may have a multilayer planar construction including a first material layer  44 , such as, but not limited to fiberglass epoxy or thermoset laminate of low relative dielectric constant (DK) typically in the range of DK=2 to DK=5; a second patterned metallization layer  45  of copper, silver-filled paste or other electrical conductor which may be deposited or printed on one side of the first layer  44  and may have a material thickness of about 0.7 to 1.4 mils for optimal operation, thereby forming a distributed resonant circuit; and a third material layer  46  such as a ceramic-filled laminate having a relatively high DK typically in the range of DK=20 to DK=50, whereby layer  46  may be in intimate face-to-face contact with second layer  45 . Probe  40  may have the same size and shape as internal antenna  50  for optimal operation. An important characteristic of probe  40  is that it functions as an anti-resonant network because of its high capacitance-to-inductance ratio which enables near field coupling and may be reception band selective by virtue of its unloaded high-Q quality factor. Band selectivity may provide multi-band resonance, for example, resonance for one or more frequency bands such as: 700, 850, 900, 1800, 1900, and 2100 MHz and others are possible, a highly desirable and novel characteristic. 
     An external antenna  60 , as shown physically in  FIGS. 1A ,  1 C, and  6 B may be mounted on, and in parallel alignment, with side wall  34 . Transmission line  42 , as shown in  FIGS. 1A and 6B  may be embedded within the rear panel  32  in order to connect probe  40  with external antenna  60  for RF signal transfer therebetween. Transmission line  42  may be a metallized or printed conductive strip. This arrangement enables RF transmission/reception at both the antennas  50  and  60  simultaneously while minimizing mutual interference. Antenna  60  may be mounted on enclosure  30  using a mechanical swivel joint  62  so that antenna  60  may be able to rotate between a retracted position  60 A, shown in dashed line in  FIG. 1A , and an extended position  60 B shown with solid lines. Antenna  60  may be a simple rigid rod, telescoping or other. Side wall  34  may have a recess as shown in  FIG. 1C  for securing antenna  60  when retracted. Antenna  60  may be operational in both its retracted position  60 A as well as its extended position  60 B. 
     As shown in  FIGS. 1A and 5 , sleeve  10  may have a remote antenna port  70 , molded into side wall  34  along with a toggle switch  72 . Switch  72  may function to select either external antenna  60  or a remote antenna  80  ( FIG. 5 ). A signal boosting amplifier  90  may be in signal communication with probe  40 , and switch  72  using metallized conductor paths  42  and  74 . Amplifier  90  may be single or bi-directional and may be enabled with diplexers, duplexers and automatic gain control (AGC) and other features for improved performance. Amplifier  90 , may be a planar device powered by battery  92  which may be mounted within side wall  34 . Elements  40 ,  60 ,  70 ,  72 , and  90  may be electrically interconnected using metallized or printed paths  42  and the paths  42  and elements  40 , and  90  may be embedded within rear panel  32 . This is shown in  FIGS. 6A and 6B  where enclosure  30  may be fabricated by injection molding techniques in a preferred approach where the rear panel  32  is constructed of layers  32 A and  32 B encapsulating probe  40 , amplifier  90  and said conductive interconnecting paths  42  as shown in the schematic diagram of  FIG. 5 . As described above, sleeve  10  taken by itself defines one embodiment of the present apparatus. The sleeve  10 , as nested and electronically interconnected with cell phone  20 , defines a second embodiment. 
     As shown in  FIG. 3  sleeve  10  may additionally be configured, with a radar system (“radar transceiver  230 ”) physically integrated into rear panel  32 . Radar transceiver  230  provides a means for measuring the speed of a distant object “target  205 ” as shown in  FIG. 7 , with the convenience of a cell phone  20 . The radar transceiver  230  may be a Doppler radar system or another type of radar system. In this embodiment, the phone  10  has an optical targeting device such as a cellphone camera  21  which may be used to sight on target  205 , while radar transceiver  230  measures its speed. A display such as a cellphone screen  25  may present the target  205  and its speed information as shown in  FIG. 4 . A storage medium such as a cellphone memory  23  is able to store this information while a wireless transmitter such as cellphone transceiver  26  transmits the information to one or more selected distant receivers such as other cell phones, land-line phones, automated computers, and other devices. The cellphone elements:  21 ,  23 ,  25 , and  26  are operated by a cellphone processor  22  in accordance with cellphone electrical circuit and software protocols that are well known in the field of cell phone technology. Prior to using cell phone  20  for the present application, operational software  24  is loaded into cellphone memory  23 , and then digital processor  22  carries out the instructions of software  24  in accordance with the present method as shown in  FIG. 9  and described herein. 
     Use of the cell phone camera display  25  as a targeting device allows this hand-held system to be manually positioned for viewing target  205  so as to achieve an advantageous level of accuracy in determining the target&#39;s speed rather than that of extraneous nearby objects, and also in avoiding mixed or confused determinations due to moving backgrounds as the phone  20  tracks the path of target  25 . As described, display  25  may be a solid-state display screen or it may be any other display device. Likewise, the wireless transmitter may be a phone transceiver  26  as stated, or it may be any other personal or mobile telephone or similar device. One or more of the: display  25 , memory  23 , software  24 , processor  22 , and wireless transceiver  26  may be integrated into sleeve  10 , or may be a separate component but may be interconnected as shown in  FIG. 7 . 
     As shown in  FIGS. 7 and 8 , radar transceiver  230  includes transmit-receive antenna  232 , transmit amplifier  234   f , receive amplifier  234   d , variable amplifiers  234   c , voltage controlled oscillator  234   a  (VCO), transceiver processor/controller  233  (CPU), quadrature demodulator  234   b  (DQD), analog-to-digital converter  246  (ADC), and digital-to-analog converter  244  (DAC). 
     When phone  20  is placed within sleeve  10  the link between phone  20  and radar transceiver  230  is made by, for instance connector  36  ( FIG. 3 ), or by a wireless method such as Bluetooth, or by induced signals between adjacent non-conducting elements as fully explained above. Radar transceiver  230  may use a highly directional transmit antenna to better focus radiated RF energy in the direction of target  205 . Various antenna designs may be used including a planar array of patch antenna elements, as shown in  FIG. 3 , which provide the necessary gain and directivity. The transmit-receive antenna  232  may alternately be separate antennas for receive and transmit. 
     Radar transceiver  230  utilizes the Doppler effect, as previously described, comparing a transmitted wave frequency with a bounced wave frequency to determine the shift in frequency due to the relative motion between the target  205  and the transmit/receive antenna  232 . 
     Once phone  20  is installed in sleeve  10  and software  24  is installed in memory  23  the apparatus is ready to measure the speed of a distant moving object. With the back panel  32  directed toward a moving target  205  an “app” icon is selected on display  25  which sends a start signal to radar transceiver processor  233  to initiate instructions for carrying-out a speed measurement cycle. The electrical circuit diagram of  FIG. 18  supports an understanding of this process. A radar burst (RF energy) is emitted by transmit amplifier  234   f  through antenna  232  in the direction of target  205 . This RF energy impinges on target  205  and a small amount of the RF energy signal is reflected and acquired by antenna  232 . Low noise receive amplifier  234   d  boosts the acquired reflected signal and quadrature demodulator  234   b  down-converts the signal. Demodulator  234   b  comprises high-frequency splitter  234   b - 3  which delivers the reflected signal to mixers  234   b - 2 . Low frequency splitter  234   b - 1  delivers the transmitted signal to mixers  234   b - 2 . The output from mixers  234   b - 2  is the difference between the transmitted and reflected frequencies. This difference signal is the Doppler frequency shift due to the relative velocities of sleeve  10  and target  205 . The difference signal is digitally sampled and the speed of the target is calculated by CPU  233  using the well-known formula v=Fd/2(Ft/c) and the speed information is routed to phone processor  22 . The calculated speed of the target is displayed as shown in  FIG. 4 . Alternately, the digital samples may be routed directly to phone processor  22  for speed calculation and display.  FIG. 9  is an overview of the process. 
     Radar transceiver processor  233 , driven by battery  235 , communicates with the cellphone processor  22  and also sets amplifier gain, VCO frequency, and other settings as directed by software  24 . The process is identical whether or not the phone  20  and the radar transceiver  230  are integral or separate units. When software  24  is initialized it produces a user interface on cellphone display  25  and also initiates a background process communicating with radar transceiver  230 . To acquire a speed measurement, as said, phone  20  is directed toward target  205  so that it is visible on display  25 . The software  24  enables the capture of video images using the cellphone&#39;s camera which is able to view target  205  through opening  43  in the back panel  32  of sleeve  10 . As said, speed measurements may be displayed and also recorded into memory  23  in along with video capture. 
     Sleeve  10  may further include a frequency selective repeater circuit  310  which uses frequency information received from enclosed phone  20  to adjust signal filtering in order to boost signal strength at a selected frequency. As shown in  FIGS. 10 ,  11 , and  12 , phone  20  may communicate with a base station BS as is well known. Also well known in cellular telephony, is that cell phones  20  adapt their operating frequency as dictated by the base stations BS through which they operate. This operating frequency is stored in cell phone memory. The operating frequency is transmitted by the cell phone  20  continuously in accordance with a software application  325  stored in cell phone memory and executed by the cell phone&#39;s processor  22 . Repeater  310  receives the cell phone&#39;s signal and adjusts to the operating frequency. 
       FIGS. 10 ,  11 , and  12  disclose embodiments of a repeater  310 .  FIG. 10  shows a circuit downlink path including antenna AE 1 , filter FL 1 , amplifier stage A 1 , variable filter FL 2 , amplifier stage A 2 , filter FL 3  and antenna AE 2 . An uplink path includes antenna AE 2 , filter FL 4 , amplifier stage A 3 , variable filter FL 5 , amplifier stage A 4 , filter FL 6  and antenna AE 1 . A controller C, such as model SAM9 manufactured by Atmel, Inc., receives an operating frequency designation and adjusts FL 2  and FL 5  each of which may be a model Micro-400-700 manufactured by Pole Zero, Inc. to pass only a band centered on the operating frequency. This circuit enables information relayed from base station BS to cell phone  20  to be used to adjust the band pass within the circuit so as to exclude other frequencies and noise and only repeat and boost a selected RF frequency or pass band of frequencies. In this embodiment all analog components function at RF frequencies. This has the advantage of being relatively less expensive, however, it does not achieve the out-of-band frequency and noise rejection that a circuit operating at an intermediate frequency (IF) can achieve. 
       FIG. 11  discloses a further embodiment of repeater  310  having a downlink path including antenna AE 1 , RF filter FL 1 , amplifier stage A 1 , mixer M 1 , local oscillator LO 1 , amplifier stage A 2 , IF filter FL 2 , IF variable gain amplifier stage A 3 , mixer M 2 , RF amplifier stage A 4 , RF filter FL 3  and antenna AE 2 . An uplink path includes antenna AE 2 , RF filter FL 4 , RF amplifier stage A 5 , mixer M 3 , local oscillator LO 2 , IF amplifier stage A 6 , IF filter FL 5 , variable IF amplifier stage A 7 , mixer M 4 , RF amplifier stage A 8 , RF filter FL 6 , and antenna AE 1 . As with the circuit of  FIG. 10 , controller C receives operating frequency information from cell phone  20  and adjusts their band pass by adjusting the local oscillators LO 1  and LO 2 . As above, this circuit enables information relayed from base station BS to cell phone  20  to adjust the band pass within the circuit so as to exclude other frequencies and noise and only repeat and boost a selected RF frequency or pass band of frequencies. In this embodiment the drawback of circuit  FIG. 10  is avoided since filtering and amplification functions are able to be conducted in the IF frequency range.  FIG. 12  operates in the same manner as the circuit of  FIG. 11  with the improvement of digital processing at controller C which results in an improved control over oscillators LO 1  and LO 2 . 
     In the circuits shown in  FIGS. 11 and 12  filtering and amplification is conducted in the IF range. As is known, it is difficult to build amplifiers, filters, and detectors that can be tuned to different frequencies, but it is easy to build tunable oscillators. Also, in RF communications, converting to a lower intermediate frequency offers an advantage because RF amplifiers have upper frequency gain limits so that a lower IF offers the possibility of higher gain. Also, at IF, filtering to extract a single frequency from signals that are close together is easier and noise is also easier to exclude. This is because a filter&#39;s bandwidth increases proportionately with the signal&#39;s frequency. So a narrower bandwidth and more selectivity can be achieved by converting the signal to an IF. The IF used may be 10.7 MHz or a frequency in that range.  FIG. 13  defines a method of operation of these circuits. In this method, repeater hardware and software are initialized for communications. Repeater fault detection may find positive and if so, repeater  310  is shut down awaiting instructions. If no fault is detected, phone software collects channel information from a base station BS and this information is transmitted to repeater  310 . Next, repeater  310  adjusts VCO frequency or signal filters in accordance with the channel information and adjusts RF power and gain. Repeater  310  is now able to monitor for fault detection and if detected, repeater  310  sends fault information to phone  20  and shuts down awaiting further instructions. If no fault is detected channel information is collected and this cycle is repeated continuously. 
     The antenna system  410  shown in  FIG. 14  may represent antennas AE 1  and AE 2  of repeater  310  and has broad applicability beyond such repeaters. For optimal operation elements  420  and  430  may have a length of lambda/4, 2, or 1. Elements  420  and  430  are part of the antenna structure shown and has a tuned slot element  440  positioned between the antenna elements  420 ,  430 , the tuned slot element  440  enabling preferential signal reception by the antenna elements  420 ,  430  in two selected frequency bands with the advantage of providing isolation of the radiation of each of the antenna elements  420 ,  430  from each other. The antenna elements  420 ,  430  and the tuned slot element  440  may be planar and may be electrically conductive, and mounted on a dielectric sheet  450 . Elements  420 ,  430 ,  440  may be covered by a dielectric layer (not shown). The antenna and tuned slot elements  420 ,  430 ,  440  may be of copper sheet material and the dielectric sheet  450  may be of a glass epoxy substrate material or similar substance. As shown in  FIG. 14 , the tuned slot element  440  may have two spaced apart segments, a C-shaped segment  460  and a roughly linear segment  470 . The C-shaped segment  460  may have a first linear leg  462  extending in a first direction (arrow A), and a second linear leg  464  extending in a second direction (arrow B), and the second direction may be orthogonal with respect to the first direction. The C-shaped segment  460  may also have a triangular portion  466 . The linear segment  470  may form an acute angle (a) with the triangular portion  466  and also form a second acute angle (b) with the first linear leg  462 . Spacing between the linear segment  470  and the triangular portion  466  may enable 1900 MHz signal reception by the antenna elements  420 ,  430  while spacing between the linear segment  470  and the first linear leg  462  may enable 850 MHz signal reception by the antenna elements.  FIG. 15  is a plot of antenna signal isolation (i) with respect to radio frequency (f). Curve A (solid line) is as measured with the tuned slot element  440  missing or removed, while curve B (broken line) is as measured with tuned slot element  440  as shown in  FIG. 14 . It is clear that tuned slot element  440  provides almost infinite isolation at the operating frequency F 1 . 
     The common functions of signal reception and transmission, filtering, amplification, mixing using a local oscillator, and converting between analog and digital signal forms are well known in the field so that further details of these functions and the nature of these operations is not further described herein. The “Electrical Engineering Reference Manual,” ISBN: 9781591261117 is incorporated herein by reference in its entirety to provide details and technical support related to the elements and functions presented herein. Embodiments of the subject apparatus and method have been described herein. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and understanding of this disclosure. Accordingly, other embodiments and approaches are within the scope of the following claims. 
     Applications U.S. Ser. No. 13/238,894 filed on 21 Sep. 2011, U.S. Ser. No. 13/590,053 filed on 20 Aug. 2012, U.S. Ser. No. 13/591,152 filed on 21 Aug. 2012, and U.S. Ser. No. 13/591,171 filed on 21 Aug. 2012 are hereby incorporated into this document by reference in their entirety.