Communications: radio wave antennas – Antennas – Microstrip
Reexamination Certificate
1998-03-20
2001-01-30
Lee, Benny T. (Department: 2817)
Communications: radio wave antennas
Antennas
Microstrip
C343S853000, C333S247000
Reexamination Certificate
active
06181278
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an antenna-integral high frequency circuit which is miniaturized, has light weight and is superior easy to produce, and more specifically to an antenna-integral high frequency circuit having a superior high frequency characteristic.
2. Description of the Background Art
Recently, rapid and large-capacity personal communication using a high frequency wave, such as microwave and millimeter wave, has attracted attention with the recent improvement in the processing speed of information processors and in the resolution of image processing apparatuses. In such devices, a miniaturized, light-weight and high-performance microwave and millimeter wave transmitter/receiver can be implemented by not only simply integrating a microwave and millimeter wave circuit with an antenna but by also configuring the integrated structure to make use of the high frequency characteristics of utilized microwave and millimeter wave. Japanese Patent Laying-Open No. 8-56113 discloses an invention as one of such antenna-integral microwave and millimeter wave circuits.
FIG. 1
shows a structure of an antenna-integral microwave and millimeter wave circuit disclosed in Japanese Patent Laying-Open No. 8-56113. The antenna-integral microwave and millimeter wave circuit includes a grounding conductor film
102
, a dielectric film
103
formed of silicon dioxide film, a plane antenna
104
, a semiconductor substrate
105
with a detector circuit, a microstrip line
107
for feeding power to plane antenna
104
, an output signal terminal
108
for outputting detected signals, a dielectric substrate
113
, and a slot
116
. Plane antenna
104
is formed on one surface of dielectric substrate
113
. Grounding conductor film
102
including slot
116
is formed on the other surface of dielectric substrate
113
, and dielectric film
103
is deposited thereon with grounding conductor film
102
. Microstrip line
107
and output signal terminal
108
are formed on the other surface of dielectric film
103
and are connected to semiconductor substrate
105
including the detector circuit.
Microstrip line
107
and plane antenna
104
are coupled via slot
116
using an electromagnetic field and thus form an antenna-integral microwave circuit.
However, the invention disclosed in Japanese Patent Laying-Open No. 8-56113 has the following disadvantages.
(1) an antenna grounding conductor is not present near the antenna. Accordingly, the potential of plane antenna
104
is unstable, resulting in disturbance of the radiation pattern caused by a conductor, such as metal, located near the plane antenna, degradation in radiation efficiency, a cause of noise generation and the like.
(2) Even if grounding conductor film
102
serves as the plane antenna's
104
grounding conductor, a conductor grounding the microwave and millimeter wave circuit is still not connected to the antenna grounding conductor in the vicinity of the microwave and millimeter wave circuit. Accordingly, the antenna grounding conductor can not be a true ground with respect to the microwave and millimeter wave circuit
105
grounding conductor, the reason of which will be described later. Accordingly, the detector circuit formed at semiconductor substrate
105
is unable to achieve less noisy, stable operation, resulting in unstable operation, such as parasitic oscillation, and increased parasitic capacitance. At the plane antenna
104
side, electromotive force will occur in the conductor grounding the detector circuit formed at semiconductor substrate and in the plane antenna
104
grounding conductor and thus causes an unnecessary radiation pattern with high side lobe. Furthermore, variation of the input impedance of plane antenna
104
also occurs, resulting in a cause of degradation of the radiation efficiency of plane antenna
104
and a cause of variation of the resonance frequency of plane antenna
104
.
(3) Among dielectric film
103
and dielectric substrate
113
, dielectric film
103
, connected to semiconductor substrate
105
, is in the form of a thin film. Accordingly, for the frequency regions of microwave and millimeter wave, the conductor for microstrip line
107
must have a reduced width, which will in turn cause a large transmission loss. The strength of the entirety of the antenna-integral microwave and millimeter wave circuit depends almost only on dielectric substrate
113
. However, the thickness of dielectric substrate
113
must be reduced to obtain the desired characteristic impedance (typically 50&OHgr;) for the frequencies of microwaves and millimeter waves. Accordingly, it is difficult to handle, and a high production yield cannot be expected. Particularly, such a flip-chip connection of semiconductor substrate
105
as shown in
FIG. 1
is typically made in high temperature environments and with a high current load, and a thin dielectric substrate
113
is thus not practical. The examples of dielectric film
103
include silicon dioxide, silicon nitride or polyimide. However, silicon dioxide and silicon nitride, which are resistant to heat, have low impact resistances and cracks are readily caused therein in flip-chip bonding. Polyimide is inferior in heat resistance and is thus difficult to use for flip-chip connection by thermocompression bonding, and such a technique must be employed by placing resin between semiconductor substrate
105
and dielectric film
103
to connect them through adhesion. Accordingly, the insufficient bonding in a conductor transmitting signals between semiconductor substrate
105
and output signal terminal
108
or microstrip line
107
, which is not particularly disadvantageous for direct current or low frequency, readily causes reflection in high frequency. The use of resin also increases the apparent dielectric constant of dielectric film
103
and thus results in more stringent limitations on circuit design. Furthermore, resin can inherently be significantly disadvantageous in reliability. Polyimide is relatively soft and plastically deformed and is thus difficult to repair.
(4) The deposition of only a single layer (the plane antenna
104
layer) on one surface and three layers (the grounding conductor film
102
, dielectric film
103
and microstrip line
107
layers) on the other surface of dielectric substrate
113
requires a increased number of manufacturing steps. After each step, the difference in internal stress is increased between the layer on one surface and a layer on the other surface, causing disadvantages such as bowing. It is thus difficult to obtain a good high frequency characteristic.
(5) Since not only semiconductor substrate
105
but dielectric substrate
113
(including grounding conductor film
102
, dielectric film
103
, microstrip line
107
, output signal terminal
108
, dielectric substrate
113
, plane antenna
104
and slot
116
) mounted with semiconductor substrate
105
are manufactured by a semiconductor process, caputalization and running costs are higher and the mass productivity is lower than those of e.g., thick-film print processes. Although a semiconductor process is superior in the precision in radiation pattern, thick-film print process also achieves a practically sufficient level of precision in radiation pattern. While the precision in flip-chip mounting rather depends on the precision of the flip-chip bonder, the recent bonding equipment has achieved the required precision level.
SUMMARY OF THE INVENTION
One object of the present invention is to provide an antenna-integral high frequency circuit with a stably operating high frequency circuit.
The antenna-integral high frequency circuit in one aspect of the present invention includes a first conductor layer with a microstrip antenna formed therein, a second conductor layer including a first grounding portion with a first slot coupling hole formed therein, a third conductor layer including a feeder circuit electromagnetically coupled with the microstrip antenna via the first slot coupling hole and also including
Kakimoto Noriko
Suematsu Eiji
Birch Stewart Kolasch & Birch
Lee Benny T.
Sharp Kabushiki Kaisha
LandOfFree
Antenna-integral high frequency circuit electromagnetically... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Antenna-integral high frequency circuit electromagnetically..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Antenna-integral high frequency circuit electromagnetically... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2519395