RF front-end apparatus in a TDD wireless communication system

• US 20050255812A1
• Filed: 05/17/2005
• Published: 11/17/2005
• Est. Priority Date: 05/17/2004
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Original Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Inventors: Yoon, Hyun-Su, Lee, Jong-Hyun, Ahn, Cheol-Woo, Na, Kweon
• Application Number:
  US11/130,486
• Publication Number:
  US 20050255812A1
• Time in Patent Office: Days
• US Class Current: 455/78
• CPC Class Codes: H04B 1/48 in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter H04B1/46 takes precedence

Abstract

A transmitting apparatus in a TDD wireless communication system is provided. In the transmitting apparatus, a circulator transmits a signal received from a power amplifier to an antenna feed line and transmits a signal received from the antenna feed line to a quarter-wave transmission line. The quarter-wave transmission line is installed in a reception path, for reception isolation in a transmission mode. An RF switch shorts the load of the quarter-wave transmission line to the ground or connects the load of the quarter-wave transmission line to an LNA according to a control signal. The LNA low-noise-amplifies a signal received from the RF switch.

Claims

1. A transmitting apparatus in a time division duplex (TDD) wireless communication system, comprising:

a circulator for transmitting a signal received from a power amplifier to an antenna feed line and transmitting a signal received from the antenna feed line to a quarter-wave transmission line;

the quarter-wave transmission line installed in a reception path, for reception isolation in a transmission mode; and

a radio frequency (RF) switch for shorting a load of the quarter-wave transmission line to ground or connecting the load of the quarter-wave transmission line to a low-noise amplifier (LNA) according to a control signal;

the LNA for low-noise-amplifying a signal received from the RF switch.

2. The transmitting apparatus of claim 1, further comprising an isolator for protecting an output port of the power amplifier and terminating a signal reflected back from the antenna feed line.

3. The transmitting apparatus of claim 1, wherein an impedance of the quarter-wave transmission line seen from the circulator becomes an open-circuit or short-circuit impedance according to a connection state of the RF switch.

4. The transmitting apparatus of claim 1, wherein the RF switch is a single pole double through (SPDT) switch or a single pole single through (SPST) switch.

5. The transmitting apparatus of claim 1, wherein the RF switch is implemented using a PIN diode or a transistor.

6. The transmitting apparatus of claim 1, wherein a length of the quarter-wave transmission line between the circulator and the ground is

$(\frac{\lambda }{}$

4 + λ

2 ⁢

n , n = 0 , 1 , 2 , 3 , …

⁢

 

) .

7. The transmitting apparatus of claim 1, wherein the power amplifier is biased off in a reception mode.

8. A transmitting apparatus in a time division duplex (TDD) wireless communication system, comprising:

a circulator for transmitting a signal received from a power amplifier to an antenna feed line and transmitting a signal received from the antenna feed line to a predetermined transmission line;

the transmission line connected between the circulator and a radio frequency (RF) switch; and

the RF switch for connecting a load of the transmission line to an open stub of a predetermined length or to a low-noise amplifier (LNA) according to a control signal;

the LNA for low-noise-amplifying a signal received from the RF switch.

9. The transmitting apparatus of claim 8, wherein the transmission line, the RF switch, and the open stub are connected and form a transmission line having a length of

$(\frac{\lambda }{}$

2 + λ

2 ⁢

n , n = 0 , 1 , 2 , 3 , …

⁢

 

) .

10. The transmitting apparatus of claim 8, further comprising an isolator for protecting an output port of the power amplifier and terminating a signal reflected back from the antenna feed line.

11. The transmitting apparatus of claim 8, wherein an impedance of the transmission line seen from the circulator becomes an open-circuit or short-circuit impedance according to a connection state of the RF switch.

12. The transmitting apparatus of claim 8, wherein the RF switch is a single pole double through (SPDT) switch or a single pole single through (SPST) switch.

13. The transmitting apparatus of claim 8, wherein the RF switch is implemented using a PIN diode or a transistor.

14. The transmitting apparatus of claim 8, wherein the power amplifier is biased off in a reception mode.

15. A transmitting apparatus in a time division duplex (TDD) wireless communication system, comprising:

a circulator for transmitting a signal received from a power amplifier to an antenna feed line and transmitting a signal received from the antenna feed line to a predetermined transmission line; and

the transmission line being a predetermined length installed in a reception path, a load impedance of the transmission line being an open-circuit impedance in a transmission mode.

16. The transmitting apparatus of claim 15, wherein a length of the transmission line is

$(\frac{\lambda }{}$

4 + λ

2 ⁢

n , n = 0 , 1 , 2 , 3 , …

⁢

 

) .

17. The transmitting apparatus of claim 15, wherein a length of the transmission line is

$(\frac{\lambda }{}$

2 + λ

2 ⁢

n , n = 0 , 1 , 2 , 3 , …

⁢

 

) .

18. The transmitting apparatus of claim 15, further comprising a radio frequency (RF) switch installed at a predetermined position of the transmission line, for switching a load of the transmission line to a low-noise amplifier (LNA) in a reception mode.

19. The transmitting apparatus of claim 18, wherein the RF switch is a single pole double through (SPDT) switch or a single pole single through (SPST) switch.

20. The transmitting apparatus of claim 18, wherein the RF switch is implemented using a PIN diode or a transistor.

21. The transmitting apparatus of claim 15, wherein one end of the transmission line is connected to the circulator and another end of the transmission line is grounded or formed as an open stub.

22. The transmitting apparatus of claim 15, wherein the power amplifier is biased off in the reception mode.

23. The transmitting apparatus of claim 15, further comprising an isolator for protecting an output port of the power amplifier and terminating a signal reflected back from the antenna feed line.