Transponder system and method for measurement of separation

• US 20050012653A1
• Filed: 11/05/2002
• Published: 01/20/2005
• Est. Priority Date: 11/09/2001
• Status: Active Grant

• Current Assignee: Symeo GmbH (indie Semiconductor, Inc.)
• Original Assignee: Symeo GmbH (indie Semiconductor, Inc.)
• Inventors: Heide, Patric, Vossiek, Martin, Nalezinski, Martin, Wiebking, Leif
• Granted Patent: US 7,119,736 B2
• Time in Patent Office: Days
• US Class Current: 342/42
• CPC Class Codes: G01S 13/825 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/84 for distance determination by phase measurement
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 7/352 Receivers
• CPC Class Codes: G01S 7/356 involving particularities of FFT processing
• CPC Class Codes: H01L 2223/6677 for antenna, e.g. antenna included within housing of semiconductor device
• CPC Class Codes: H01L 2224/16227 the bump connector connecting to a bond pad of the item
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA

Abstract

Separation determination systems for determining the separation between a base station and a transponder, whereby the base station includes an oscillating signal source, for generating a signal and a transmission device for broadcasting the signal. The transponder includes a receiving device, for receiving the signal from the base station, an oscillator, for generating a signal which is phase-coherent therewith and a transmission device for broadcasting the phase-coherent signal. The base station furthermore includes a receiver device, for receiving the phase-coherent signal from the transponder and a separation determination device for determining the distance between base station and transponder. The system and components may be improved whereby the oscillator in the transponder is energized with the received signal in order to generate a quasi-phase-coherent signal.

Claims

1. Method for determining the distance (dist) between a base station (BS) and at least one transponder (TR) which comprises

radiating out by the base station (BS) a signal (s_tx(t)) from a base station oscillator (OSZ_B);

using an oscillating oscillator (OSZ_T) of the transponder (TR) to generate a signal (s_OSZ(t)) which is phase-coherent with and based on the signal (e_rxt(t)) received from the base station (BS), and radiates out this signal,

determining the distance (dist) is the base station (BS) by reference to the phase-coherent signal (s_rx(t)) received from the transponder (TR), wherein

the oscillator (OSZ_T) for generating the phase-coherent signal (s_OSZ(t)) is excited quasi-phase-coherently with the received signal (s_rxt(t)).

2. Distance determination system for determining the distance (dist) between a base station (BS) and at least one transponder (TR), wherein

the base station (BS) has an oscillating signal source (OSZ_B) for generating a signal (s_tx(t)) and a transmission device (ANT_B) for radiating out the signal (s_tx(t)),

the transponder (TR) has a receiving device (ANT_T) for receiving the signal (e_rxt(t)) from the base station (BS), an oscillator (OSZ_T) for generating a signal (s_OSZ(t)) which is phase-coherent with it, and a transmission device (ANT_T) for radiating out the phase-coherent signal (s_OSZ(t)),

the base station (BS) has in addition a receiving device (ANT_B) for receiving the phase-coherent signal (s_OSZ(t)) from the transponder (TR) and distance determination equipment (RMIX, FLT, DEMOD) for determining the distance (dist) between the base station (BS) and the transponder (TR), and

the oscillator (OSZ_T) in the transponder (TR) is excited with the received signal (S_rxt(t)) into generating a quasi-phase-coherent signal (s_OSZ(t)).

3. Base station (BS) for determining the distance to a transponder (TR) using a distance determination system in accordance with claim 2, wherein

the distance determination equipment (RXMIX, FLT, DEMOD) in the base station (BS) has a mixer (RXMIX) for mixing the quasi-phase-coherent signal (s_rxt(t)) received from the transponder (TR) and the instantaneous transmit signal (s_tx(t)) to form a mixture signal (s_mix(t)).

4. Base station (BS) in accordance with claim 3, wherein the distance determination equipment (RXMIX, FLT, DEMOD) is constructed to form the mixture signal (s_mix(t)) given by

S_mix(t)=cos (t·

ω

_sw+τ

·

(ω

_c+ω

_sw))

where ω

_c is the central frequency of the base station oscillator (OSZ_B), ω

_SW is the modulation frequency of the transmit signal s_tx(t) from the base station (BS), t is the time in the interval 0-Ts, and τ

is the time for the propagation of the signals over the distance (dist) between the base station (BS) and the transponder (TR).

5. Base station (BS) in accordance with claim 3, wherein

the distance determination equipment (RXMIX, FLT, DEMOD) has demodulation equipment (DEMOD, GR, TP), for reducing or eliminating changes in the voltage of the mixture signal (s_mix(t)), over the time interval (0-TS) between the measurement being switched on and switched off in the base station (BS), for the generation of a measurement signal (s_mess(t)).

6. Base station (BS) in accordance with claim 3, wherein

the distance determination equipment (RXMIX, FLT, DEMOD) has demodulation equipment (DEMOD, ZFMIX, LO, TP) for mixing down the mixture signal s_mix(t), in particular with a frequency near to or the same as a clock frequency (f_mk), to a frequency significantly lower than the clock frequency (f_mk), for switching the oscillator (OSZ_T) in the transponder (TR) cyclically on and off, followed by the filtering out of high-frequency components to generate a measurement signal (s_mess(t)).

7. Base station (BS) in accordance with claim 3, wherein the distance determination equipment (RXMIX, FLT, DEMOD) is constructed to modulate the modulation frequency (ω

_SW) of the transmit signal s_tx(t) of the base station (BS), in particular such that

${\mathrm{\omega <br><br>}}_{\mathrm{sw}}=\frac{2·<br><br>\mathrm{\pi <br><br>}·<br><br>B·<br><br>t}{T}$

where T is a length of time over which the frequency is modulated across the bandwidth B.

8. Base station (BS) in accordance with claim 3, wherein the distance determination equipment (RXMIX, FLT, DEMOD) is constructed to form the resulting FMCW signal (s_messfmcw(t)) as

$$

⁢

 

 

 

s mess fmcw ⁡

( t ) = ⁢

⁢

 

⌈

cos ⁢

( ω

c ·

τ

+ 2 ·

π

·

B ·

t ·

τ

T + π

·

B ·

t ·

T s T ) ·

⁢

⌉

sin ⁡

( π

·

B ·

t ·

T s T ) (  

⁢

π

·

B ·

t T )

9. Base station (BS) in accordance with claim 3, wherein the distance determination equipment (RXMIX, FLT, DEMOD) is constructed for determining the distance (dist) from the measuring frequency (f_mess) which corresponds to the normal FMCW measurement frequency (Frequency Modulated Continuous Wave) displaced by a frequency component (Δ

b=B*Ts/(2 T)).

10. Base station (BS) in accordance with claim 8, wherein the distance determination equipment (RXMIX, FLT, DEMOD) is oriented towards the performance of a Fourier transformation of the amplitude-weighted measurement signal (s_messfmcw(t)) in the frequency domain, so that edges of a left and a right sideband of at least one squarewave function which results determine the distance between the base station (BS) and the transponder (TR).

11. Transponder (TR) or base station (BS) for claim 2, wherein the transponder (TR) or the base station (BS), is constructed as an LTCC (Low Temperature Cofired Ceramic) module (LM), or making use of at least one LTCC module (LM).

12. Transponder (TR) for determining its distance from a base station (BS) using a distance determination system in accordance with claim 2, with signal generation equipment (OSZ_T, CLK/Sw) for generating an oscillator signal (s_OSZ(t)) from a signal received by the transponder (e_rxt(t)=s_tx(t-τ

/2)) using an oscillator (OSZ_T) and a switching facility (CLK/Sw) for switching the oscillator (OSZ_T) cyclically on and off, for generating an oscillator signal defined by

$s_{\mathrm{rx}}<br><br>\left(t\right)=s_{\mathrm{osz}}<br><br>\left(t-\frac{\mathrm{\tau <br><br>}}{2}\right)=\sin <br><br>\left({\mathrm{\omega <br><br>}}_{\mathrm{osz}}·<br><br>t-\left({\mathrm{\omega <br><br>}}_c+{\mathrm{\omega <br><br>}}_{\mathrm{sw}}\right)·<br><br>\mathrm{\tau <br><br>}+{\mathrm{\varphi <br><br>}}_o\right)$

where ω

_c is the central frequency of the base station oscillator (OSZ_B), ω

_SW is the modulation frequency of the transmit signal s_tx(t) from the base station (BS), t is the time in the interval 0-Ts, and τ

is the time for the propagation of the signals over the distance (dist) between the base station (BS) and the transponder (TR) and φ

₀ is an arbitrary phase offset.

13. Distance determination system in accordance with claim 2, wherein a modulation (f_mk) is used for switching the oscillator (OSZ_T) in the transponder (TR) on and off, for transmitting additional information from the transponder (TR) to the base station (BS).

14. Distance determination system in accordance with claim 2 wherein a modulation (f_mk) for switching the oscillator (OSZ_T) in the transponder (TR) on and off is assigned individually to each of a large number of transponders (TR).