EP0606514A1

EP0606514A1 - Microstrip element phase-shift array antenna

Info

Publication number: EP0606514A1
Application number: EP93100583A
Authority: EP
Inventors: Rolan Wu
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-01-15
Filing date: 1993-01-15
Publication date: 1994-07-20

Abstract

An antenna used in mobile radio systems and communication systems (e.g., mobile telephone systems) for receiving and transmitting radio signals from/to a remote signal source. The antenna is designed in a microstrip form by microwave techniques and receives and transmits radio signals in a low-frequency region of 535 KHz -- 1 GHz. The antenna comprises a signal processing circuit and a plurality of phase-shift elements respectively installed on different positions of the signal processing circuit to form an element array with each of the elements having a respective phase angle so as to receive the signals coming from every directions and transmit the signals omnidirectionally.

Description

BACKGROUND OF THE INVENTION

The present invention is related to an antenna, especially to an antenna designed in microwave technique and applicable in automobiles, mobile telephones and other radio communication systems for receiving and transmitting signals within low-frequency regions.
The antenna of the present invention can be concealed in a metal container such as a housing of a vehicle for receiving and transmitting radio signals. At the present, the automobile antenna is designed co-axially and should be positioned outside of the vehicle for preventing the radio signals from being obstructed by the housing of the vehicle. Such arrangement has disadvantages as follows: (1) the antenna is subject to shakes during the motion of the vehicle so that the reception and transmission of the radio signals will be influenced; and (2) the operation of the antenna is controlled by mechanical or electric means which is inconvenient in use.
To solve the problems mentioned above, one kind of the antenna systems has been developed of which the antenna is hidden inside of the vehicle. In such system, the antenna should be inlaid in a glass (e.g. the back glass of the vehicle) to prevent from shaking. The antenna system, however, receives the radio signals only in specific directions but not in omnidirection. Therefore, the reception of the signals is worse. Besides, such antenna is also designed by the co-axial technique and can not be concealed in a metal cover.
Further, in the current radio system, the signals received by the antenna before being utilized by the radio system should be converted to matched signals of the radio system via a matching circuit. The circuitry of the antenna system is very complex.

SUMMARY OF THE INVENTION

One object of the present invention is to provide an antenna which is designed by microwave techniques to receive and transmit radio signals within low-frequency regions. The antenna of the present invention is a microstrip form and the volume thereof is very small so that the antenna can be mounted very easily.
The other object of the present invention is to provide an antenna which receives and transmits signals in omnidirection and can be positioned in anywhere in the vehicle.
The antenna in accordance with the present invention can be used in radio systems and radio communication systems which can simultaneously receive and transmit the radio signals without an additional antenna. The antenna of the present invention can also be concealed in the housing of the vehicle so that all the disadvantages occurred in the prior art can be overcome. More particularly, the antenna is operated in duplex manner which can transmit the radio signals radially and omnidirectionally.
These and other objects, advantages and features of the present invention will be more fully understood and appreciated by reference to the written specification.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view of the antenna in accordance with the present invention;
Fig. 2 is a circuitry block diagram showing the receiving manner of the antenna of the present invention; and
Fig. 3 is a circuitry block diagram showing the transmitting manner of the antenna of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, the antenna 1 of the present invention is microstrip-typed and is made of magnetic materials which is arranged in a spiral form according to an electronic magnetic and microwave techniques. That is, the spiral form of the magnetic material is not a smooth curve and the width thereof is not uniform so as to form a signal-processing circuit having a number of processing means. In addition to the signal-processing circuit, the antenna 1 further comprises a plurality of phase-shift elements 11 settled on appropriate positions of the spiral magnetic material for receiving and transmitting radio signals.
As shown in Fig. 1, the phase-shift elements 11 are set on different positions of the antenna 1 so that the elements 11 have different phase angles respectively, making the phase-shift elements 11 be capable of receiving radio signals coming from various signal sources and transmitting signals in omnidirection. Owing to the above features, the antenna 1 in accordance with the present invention can be positioned in a metal cover and especially, is applicable in mobile articles, such as automobiles and mobile telephones for receiving and transmitting radio signals.
Further, the signal-processing circuit of the present invention can process the radio signals in a duplex manner. A duplex means (shown in fig. 3) can make the radio signals transmitted in radial direction first (e.g., in the vehicle) and then in omnidirection (e.g., 3 meters apart from the vehicle) to reduce interferences. The signal-processing manner of the antenna will be described detailedly hereinafter.
Fig. 2 is a receiving and signal-processing manner of the antenna 1 of the present invention. In view of Fig. 2, it can be seen that the signal-processing circuit comprises a filtering means 21 and a compensation means 22. The radio signals transmitted from a remote signal source T are received by the phase-shift elements 11 and then are sent to the signal-processing circuit for transforming to be receivable signals of a radio system 3 of a vehicle or a receiver 4 of a mobile telephone. After received by the phase-shift elements 11, the radio signals are first filtered by the filtering means 21 to filter noise and undesired signals and then are compensated and converted by the compensation means 22 to provide matching signals of the radio system or mobile telephone system. Finally, the signals are sent to the radio system or mobile telephone system for reception. In the present invention, there is no need to have an additional matching circuit as mentioned in the prior art.
The signal-processing circuit of the present invention further comprises a duplex means 23 (shown in Fig. 3) which is particularly suitable when the antenna 1 of the present invention is used for transmitting radio signals (e.g., in the case of mobile telephone systems) to a remote signal source T' (which may not be the same as the source T shown in Fig. 2). As shown in Fig. 3, the signals are first filtered by the filtering means 21 to filter noise and undesired signals and then are compensated and converted by the compensation means 22. Finally, the compensated signals are transmitted by the phase-shift elements 11. When the antenna of the present invention is used in an automobile telephone system, the signals, especially in the transmission state, are subject to interferences of the internal equipments and the housing of the vehicle. The duplex means 23 is designed to overcome this problem by making the signals transmitted in radial directions first and then in omnidirection after the signals being transmitted outwardly 3 meters (for example) apart from the vehicle.
The signal-processing circuit further comprises a synchronous means 24 for synchronizing the reception and transmission speeds of signals of each of the phase-shift elements 11. The synchronous means 24 outputs a synchronous signal to each of the phase-shift elements 11 to control said element 11 to receive and transmit the radio signals with same speeds.
According to the present invention, the duplex means 23 is used to make the signals transmitted radially first and omnidirectionally when the signals are 3 meters (for example) apart from the vehicle in which the transmission antenna is set. Accordingly, it can ensure that the signals can be transmitted outwardly to a receiver of the remote signal source without interferences.
The signal-processing circuit of the antenna of the present invention is manufactured by microwave magneto-chemical materials so that the signal-processing circuit would have a magnetization characteristic for providing the functions of magnetism coupling, phase-modulation, phase pre-correction and phase pre-compensation. As a result, the reception and transmission functions of the antenna are largely improved.
Moreover, the antenna of the present invention can be manufactured to be disk-shaped (as shown in Fig. 1) which will occupy a small volume so that the antenna can be positioned in anywhere of the vehicle. As the phase-shift elements 11 are arranged in an array forming a variety of receiving/transmitting phases, the antenna can be concealed in metal housings and even in mobile articles without influencing the reception/transmission functions thereof. Besides, it is first created that the antenna of the present invention designed by microwave techniques is applicable in a low-frequency region between 535 KHz --1 GHz.
As various embodiments might be made of the above invention without departing from the scope of the invention, it is to be understood that all matter herein interpreted as illustrative and not in a limiting sense.

Claims

A microstrip antenna comprising a signal-processing circuit and a plurality of phase-shift elements for receiving and transmitting radio signals, wherein:
said phase-shift elements being respectively installed on different positions of the signal-processing circuit so that said phase-shift elements have respective phase angles and can receive radio signals coming from every directions and transmit radio signals omnidirectionally; and
said signal-processing circuit being made of magnetic materials and arranged in a spiral form and comprising a filtering means for filtering the radio signals received or transmitted by said phase-shift elements and a compensation means for compensating said filtered radio signals to provide a matching function with a remote radio communication system.
The microstrip antenna as claimed in Claim 1, further comprising a duplex means for controlling said phase-shift elements to transmit said radio signals in radial directions and in omnidirection.
The microstrip antenna as claimed in Claim 1 being disk-shaped.
The microstrip antenna as claimed in Claim 1, wherein said phase-shift elements receive and transmit the radio signals in a frequency region of 535 KHz - 1 GHz.
The microstrip antenna as claimed in Claim 1, wherein said signal-processing circuit is manufactured by microwave magneto-chemical materials so as to have a magnetization characteristic.