EP0959567A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Diplexer for mobile phone
Assignee: Siemens AG
•
Filing: 1998-05-19
•
Granted: —
•
Expires: 2018-05-19
Abstract
Abstract The invention relates to a mobile phone (1) for at least two frequency bands (5, 10). An antenna (20) is coupled to a multiplex type filter (25). The multiplex type filter (25) contains at least two disparate bandpass filters (30, 35) for separate reception or transmission frequency bands (5, 10). A first bandpass filter (30) of the at least two disparate bandpass filters (30, 35) has as a passband a first frequency band (5). A second bandpass filter (35) of the at least two disparate bandpass filters (30, 35) has as a passband a second frequency band (10). An input impedance of the first bandpass filter (30) in the second frequency band (10) is higher than an input impedance of the second bandpass filter (35) in the second frequency band (10), and an input impedance of the second bandpass filter (35) in the first frequency band (5) is higher than an input impedance of the first bandpass filter (30) in the first frequency band (5), so that coupling of signal power at frequencies in the first frequency band (5) to the second bandpass filter (35) and coupling of signal power at frequencies in the second frequency band (10) to the first bandpass filter (30) is essentially reduced.
Inventors
- 👤 Pia Thomsen
- 👤 Niels Ole Norholm
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 14:41
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/005; H04B1/0053; H04B1/006; H01; H01P; H01P1/00; H01P1/20; H01P1/213; H04B1/0057; H04B1/38; H04B1/40; H04B1/403; H04B1/406
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
204 words
Mobile phone (1) for at least two frequency bands (5,
10), characterized by an antenna (20) coupled to a multiplex
type filter (25), the multiplex type filter (25) containing
at least two disparate bandpass filters (30, 35) for either
separate reception or separate transmission frequency bands
(5, 10), a first bandpass filter (30) of the at least two
disparate bandpass filters (30, 35) having as a passband a
first frequency band (5), a second bandpass filter (35) of
the at least two disparate bandpass filters (30, 35) having
as a passband a second frequency band (10), an input
impedance of the first bandpass filter (30) in the second
frequency band (10) is higher than an input impedance of the
second bandpass filter (35) in the second frequency band
(10), an input impedance of the second bandpass filter (35)
in the first frequency band (5) is higher than an input
impedance of the first bandpass filter (30) in the first
frequency band (5), so that coupling of signal power at
frequencies in the first frequency band (5) to the second
bandpass filter (35) and coupling of signal power at
frequencies in the second frequency band (10) to the first
bandpass filter (30) is essentially reduced.
Claim 2
Dependent Claim
222 words
Mobile phone (1) according to claim 1, characterized in
that the multiplex type filter (25) contains a third
bandpass filter (40) for a third frequency band (15),
separated from the first and the second frequency band (5,
10), the third bandpass filter (40) having as a passband the
third frequency band (15), an input impedance of the third
bandpass filter (40) in the first and in the second
frequency band (5, 10) is higher than an input impedance of
the first bandpass filter (30) in the first frequency band
(5) and higher than an input impedance of the second
bandpass filter (35) in the second frequency band (10), an
input impedance of the first bandpass filter (30) in the
third frequency band (15) is higher than an input impedance
of the third bandpass filter (40) in the third frequency
band (15), an input impedance of the second bandpass filter
(35) in the third frequency band (15) is higher than an
input impedance of the third bandpass filter (40) in the
third frequency band (15), so that coupling of signal power
at frequencies in the first and second frequency band (5,
10) to the third bandpass filter (40) and coupling of signal
power at frequencies in the third frequency band (15) to the
first and second bandpass filters (30, 35) is essentially
reduced.
Claim 3
Dependent Claim
45 words
Mobile phone (1) according to claim 1, characterized by
the first frequency band (5) at approximately 900 MHz,
especially the GSM 900 MHz band (global system for mobile
communications), and the second frequency band (10) at
approximately 1800 MHz, especially the GSM 1800 MHz band.
Claim 4
Dependent Claim
24 words
Mobile phone (1) according to claim 2, characterized by
the third frequency band (15) at approximately 1900 MHz,
especially the GSM 1900 MHz band.
Claim 5
Dependent Claim
92 words
Mobile phone (1) according to any one of the preceding
claims, characterized in that in the multiplex type filter
(25), at least one of the bandpass filters (30, 35, 40)
follows a matching circuit (45, 50, 55), the matching
circuit (45, 50, 55) transforming a low input impedance of
the at least one of the bandpass filters (30, 35, 40) to a
high input impedance in at least those of the frequency
bands (5, 10, 15) different from the passband of the at
least one of the bandpass filters (30, 35, 40)
Claim 6
Dependent Claim
21 words
Mobile phone (1) according to claim 5, characterized in
that the matching circuit (45, 50, 55) is a transmission
line (60)
Claim 7
Dependent Claim
38 words
Mobile phone (1) according to claim 6, where the length
of the transmission line (60) corresponds approximately to a
quarter of the wavelength of the center frequency of the
passband of the corresponding bandpass filter (30, 35, 40).
Claim 8
Dependent Claim
61 words
Mobile phone (1) according to any one of the preceding
claims, characterized in that the multiplex type filter (25)
having one common input (65), the input (65) is shared by
the at least two bandpass filters (30, 35), and the
multiplex type filter (25) having an output (70, 75) for
each of the at least two bandpass filters (30, 35)
respectively.
Claim 9
Dependent Claim
67 words
Mobile phone (1) according to any one of claims 1 to 7,
characterized in that the multiplex type filter (25) having
one common output (115), the at least two bandpass filters
(30, 35) of the multiplex type filter (25) sharing the
common output (115), and the multiplex type filter (25)
having an input (85, 90) for each of the at least two
bandpass filters (30, 35), respectively.
Claim 10
Dependent Claim
26 words
Mobile phone (1) according to any one of the preceding
claims, characterized in that the multiplex type filter (25)
is a SAW (surface acoustic wave) filter.
Claim 11
Dependent Claim
39 words
Mobile phone (1) according to any one of claims 1 to 9,
characterized in that the multiplex type filter (25) is a
strip line filter, a microstrip filter, a multilayer filter,
a ceramic filter or based on helical resonators.
References Cited (Backward Citations)
EP0465315A1
Cited
EP0575174A1
Cited
US5534829A
Cited
US5471164A
Cited
EP0747988A1
Cited
US5731746A
Cited
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.