Near-field induction voltage boost circuit

1. A near-field circuit configured to be coupled to a near-field antenna wherein the near-field antenna includes, a first conductive structure, a second conductive structure, a first feeding connection, and a second feeding connection, wherein the conductive structures are configured to transmit and/or receive non-propagating quasi-static electric (E) field signals, the near-field circuit comprising:

a transmit circuit having a first coupling connection and a second coupling connection;

a voltage boost circuit configured to be coupled in series between the first coupling connection of the transmit circuit and the first feeding connection of the near-field antenna;

wherein the second coupling connection of the transmit circuit is configured to be coupled to the second feeding connection of the near-field antenna.

2. The circuit of claim 1 :

wherein the first conductive structure and the second conductive structure together form a short loaded dipole electric near-field antenna.

3. The circuit of claim 1 :

wherein the voltage boost circuit is a capacitor;

wherein one end of the capacitor is coupled to the first coupling connection of the transmit circuit; and

wherein another end of the capacitor is configured to be coupled to the first feeding connection of the near-field antenna.

4. The circuit of claim 3 :

wherein a voltage between the first conductive structure and the second conductive structure is, Vant=V RFIC (Ct+Ck)/Ck; and

wherein,

Vant=a voltage between the first and second conductive structures,

V RFIC =an output voltage of the near-field circuit,

Ct=a tuning capacitance in the near-field circuit, and

Ck=a capacitance of the voltage boost circuit capacitor.

5. The circuit of claim 3 :

further comprising a tuning circuit having a tuning capacitance configured to adjust a resonance frequency and/or bandwidth of the near-field antenna.

6. The circuit of claim 5 :

wherein the tuning capacitance is equal to or greater than the voltage boost circuit capacitance.

7. The circuit of claim 5 :

wherein a ratio of the voltage boost circuit capacitance to the tuning capacitance is configured to adjust a voltage gain between the near-field circuit and the near-field antenna.

8. The circuit of claim 1 :

wherein the voltage boost circuit is an amplifier configured to adjust a voltage gain between the near-field circuit and the near-field antenna.

9. The circuit of claim 1 :

wherein the voltage boost circuit is a negative impedance element configured to adjust a voltage gain between the near-field circuit and the near-field antenna.

10. The circuit of claim 1 :

wherein the voltage boost circuit a negative coil configured to adjust a voltage gain between the near-field circuit and the near-field antenna.

11. The circuit of claim 1 :

wherein the voltage boost circuit is physically positioned closer to the transmit circuit than the near-field antenna.

12. The circuit of claim 1 :

wherein the near-field antenna is an electric induction (NFEI) antenna.

13. The circuit of claim 1 :

wherein the near-field antenna further includes, a first magnetic coil coupled to the first conductive structure and the first feeding connection; and

wherein the first magnetic coil is configured to transmit and/or receive non-propagating quasi-static magnetic (H) field signals.

14. The circuit of claim 13 :

wherein the near-field antenna is an electromagnetic induction (NFEMI) antenna.

15. The circuit of claim 13 :

further comprising a tuning circuit having a tuning capacitance and tuning resistor configured to adjust a resonance frequency and/or bandwidth of the near-field antenna;

wherein the voltage boost circuit is configured to provide a voltage gain between the near-field circuit and the near-field antenna;

wherein the first magnetic coil includes an inductance having a tolerance variation; and

wherein a maximum value of the voltage gain is limited by a maximum value of the tuning capacitance and the tolerance variation of the first magnetic coil inductance.

16. The circuit of claim 15 :

wherein the voltage boost circuit includes a variable capacitance; and

wherein the maximum value of the voltage gain is set based on the variable capacitance.

17. The circuit of claim 1 :

wherein the near-field antenna further includes, a first magnetic coil and a second magnetic coil;

wherein the first magnetic coil is coupled between the first feeding connection and the second feeding connection;

wherein the second magnetic coil is coupled between the first feeding connection and the first conductive structure;

wherein the first and second magnetic coils are coupled in series; and

wherein the first and second magnetic coils are configured to transmit and/or receive non-propagating quasi-static magnetic (H) field signals.

18. The circuit of claim 17 :

wherein the voltage boost circuit is a capacitor;

wherein one end of the capacitor is coupled to the first coupling connection of the transmit circuit;

wherein another end of the capacitor is configured to be coupled to the first feeding connection of the near-field antenna;

wherein a voltage between the first conductive structure and the second conductive structure is Vant=Vcoil+k Vcoil; and

wherein,

Vcoil=V RFIC (Ct+Ck)/Ck,

k=M√{square root over (L 1 *L 2 )},

Vant is a voltage between the first and second conductive structures,

Vcoil=a voltage across the first magnetic coil,

k=a magnetic coupling factor between the first magnetic coil and the second magnetic coil,

L 1 =an inductance of the first magnetic coil,

L 2 =an inductance of the second magnetic coil,

M=a mutual inductance between the first and second magnetic coils,

V RFIC =an output voltage of the near-field circuit,

Ct=a tuning capacitance in the near-field circuit, and

Ck=a capacitance of the voltage boost circuit capacitor.

19. A near-field device, comprising:

a near-field antenna including,

a first conductive structure;

a second conductive structure;

a first feeding connection; and

a second feeding connection;

wherein the conductive structures are configured to transmit and/or receive non-propagating quasi-static electric (E) field signals;

a transmit circuit having a first coupling connection and a second coupling connection; and

a voltage boost circuit coupled in series between the first coupling connection of the transmit circuit and the first feeding connection of the near-field antenna;

wherein the second coupling connection of the transmit circuit is coupled to the second feeding connection of the near-field antenna.