Ring resonator and antenna

Details Ring resonator and antenna Ring resonator and antenna

2001-12-12

2003-07-29

Phan, Tho (Department: 2821)

Communications: radio wave antennas

Antennas

High frequency type loops

C343S742000, C343S744000, C343S866000

Reexamination Certificate

active

06600451

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a high-frequency ring resonator for use in a radio communication apparatus and a ring antenna.
BACKGROUND OF THE INVENTION
A radio communication apparatus is advantageous in that it can be easily configured as a communication apparatus excellent in portability, as compared to a wire communication apparatus. This apparatus in many cases requires size-reduction in order to enhance carryability. Consequently, size reduction is required also for the elements constituting the apparatus.
The small resonator, for use in high-frequency filters, oscillators or the like, often utilizes a TEM-mode one-wavelength ring resonator as shown in FIG.
1
.
The upper conductor
101
and the lower conductor
102
are structured on the opposite surfaces of a dielectric substrate
100
, thereby constituting a one-wavelength ring resonator. An input signal is applied through a coupling capacitor
103
to point a on the upper conductor
101
. A resonant signal is outputted from point b where the electrical length corresponds to the half wavelength at the resonant frequency, and passes through the coupling capacitor
104
, thus configuring a high-Q resonator.
The resonator, because an upper conductor
101
, coupling capacitors
103
,
104
, etc. can be formed on a dielectric substrate
100
by a print or photo-etching technique, is well suited for mass production and has good reproducibility of desired characteristics.
In order to reduce the size of the one-wavelength resonator, there is a proposal that a gap is provided in the upper conductor
101
as a resonant line, a capacitance is connected in the gap, and a transmission line is coupled to the resonator, thereby extracting an output. This configuration can decrease the resonant-circuit resonant line length down to one wavelength or smaller, hence allowing for making a miniature resonator structure. However, the Q-value of the resonator might decrease due to lumped constant elements in the resonant circuit. Thus, this resonator tends to suffer deterioration in Q-value, more so than the one-wavelength ring resonator.
Meanwhile, a ring antenna is well known as an antenna for use in an RF apparatus.
FIG. 2
shows a conventional structure of a ring antenna. The conductor
1101
, being a balanced circuit having an electrical length corresponding to one wavelength at the resonant frequency, is connected at its end with a balun
1102
. Output is generated from the unbalanced circuit of the balun
1102
.
The ring antenna, simple in structure, is well suited for mass production and has good reproducibility of desired characteristics.
However, the ring antenna, on the principle, requires a line length corresponding to one wavelength. This increases the size particularly in a frequency band having a long wavelength, resulting in difficulty in manufacturing a portable radio frequency apparatus.
SUMMARY OF THE INVENTION
It is a first object of the resent invention to reduce the size of the resonator without encountering deterioration in Q-value.
A second object is to reduce the size of the ring antenna structure.
According to the present invention, when the transmission line in a TEM mode is structured by two conductors, the ends of these line are connected with opposite polarity to the ends of the other line, thereby constituting a resonator resonating in a half-wavelength mode. This structure, free of line discontinuity to deteriorate the Q value, can constitute a resonator having a high Q-value equivalent to that of the one-wavelength resonator. Moreover, the transmission line length is satisfactorily a half of that of the one-wavelength resonator. Accordingly, it is possible to miniaturize the form with a structure that has little Q-value deterioration.
Meanwhile, because there is no line discontinuity deteriorating characteristics, an antenna can be structured high in efficiency equivalent to the one-wavelength ring antenna. Accordingly, it is possible to reduce the size down to half that of the conventional antenna.
Furthermore, size reduction is further possible by inserting a capacitance element in the ring antenna circuit.


REFERENCES:
patent: 5734353 (1998-03-01), Van Voorhies
patent: 6204821 (2001-03-01), Van Voorhies
patent: 6259413 (2001-07-01), Schmidt et al.

Affiliated with

Also associated with

Rating

Ring resonator and antenna does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Ring resonator and antenna, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ring resonator and antenna will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3011207