Structure of a radio-frequency front end

• US 6,961,544 B1
• Filed: 07/13/2000
• Issued: 11/01/2005
• Est. Priority Date: 07/14/1999
• Status: Expired due to Fees

• Current Assignee: Cantor Fitzgerald Securities (Cantor Fitzgerald, L.P.)
• Original Assignee: Filtronic LK Oy
• Inventors: Hagström, Panu
• Primary Examiner(s): Kincaid, Lester G.
• Assistant Examiner(s): NGUYEN, KHAI MINH
• Application Number:
  US10/030,555
• Time in Patent Office: 1,937 Days
• Field of Search: 455/129, 455/550.1, 455/73, 455/82, 455/300, 455/86, 455/90.3, 455/83, 455/575.5, 455/575.7, 455/79, 455/78, 343/703, 343/702, 343/752, 343/745
• US Class Current: 455/82
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40
• CPC Class Codes: H03D 7/165 at least two frequency changers being located in different paths, e.g. in two paths with carriers in quadrature combined with amplitude demodulation H03D1/2245, combined with angle demodulation H03D3/007; N-path filters H03H19/002
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes

Abstract

The invention relates to an integrated structure of a radio-frequency front end of a communications apparatus. The antenna of the communications apparatus is constructed on a printed circuit board. To this antenna board (310), on its ground plane side, a second circuit board (321) is attached by means of a rigid protective frame (410), which second circuit board includes the other parts of the radio-frequency front end. Between the parts impedance levels are used that are appropriate from the electrical operation perspective. All said parts together form an integrated component (400) to be located inside the housing of the communications apparatus. The advantage of the invention is that it requires a smaller number of components needed for matching between the RF parts, and makes possible a greater sensitivity of the receiver as well as a better transmitter efficiency than prior art structures.

Claims

1. A structure of a radio frequency front end comprising as functional units an antenna and at least one bandpass filter and at least one amplifier, in which front end active and passive component parts have been integrated, the structure further comprising:

an antenna circuit board having a first surface on which there is at least one radiating element and on a second surface of which there is a conductive plane;

a second circuit board having a first surface on which said at least one filter and at least one amplifier are supported, and a second surface of which is conductive; and

a protective frame such that the antenna circuit board second surface, the second circuit board first surface and the protective frame form a substantially closed space;

wherein the antenna circuit board, the second circuit board with attached units and the protective frame form a single solid component, and the distance between the second circuit board and the antenna circuit board in said component is substantially smaller than a quarter of a wavelength corresponding to any operation frequency of said front end.

2. The structure of claim 1, comprising both a transmit and a receive branch, said functional units being a duplex filter, a low-noise amplifier and a receive filter, a transmit filter and a power amplifier, and a directional coupler.

3. The structure of claim 1, comprising both a transmit and a receive branch, said functional units being an antenna filter and antenna switch, a low-noise amplifier and a receive filter, a transmit filter and a power amplifier, and a directional coupler.

4. The structure of claim 2, said functional units further being at least a transmit branch mixer, a receive branch mixer, a modulator, a demodulator and filters associated with these.

5. The structure of claim 1, said antenna being a multi-frequency antenna having at least two radiating elements on the antenna circuit board.

7. The structure of claim 3, said functional units further being at least a transmit branch mixer, a receive branch mixer, a modulator, a demodulator and filters associated with these.

6. A communications apparatus having a radio-frequency front end, which comprises:

an antenna circuit board having a first surface on which there are formed radiating elements of an antenna of the communications apparatus and on a second surface of which there is a conductive plane;

a second circuit board by which functional units of said front end are supported on a first surface, and a second surface of which is conductive; and

a protective frame such that the antenna circuit board second surface, the second circuit board first surface and the protective frame form a substantially closed space;

wherein the antenna circuit board, the second circuit board with attached units and the protective frame form a single solid component, and the distance between the second circuit board and the antenna circuit board in said component is substantially smaller than a quarter of a wavelength corresponding to any operation frequency of said front end, and said component is completely inside covers of the communications apparatus.