The present disclosure relates to a coupler.
A connector or coupler is used for electrically connecting two devices so as to pass a signal. A connector may include a female metal contact on one side, which engages with a male metal contact on the other side. However, such connectors may suffer from the following problems:
1. The connection performance may degrade due to oxidation and wear after time.
2. When the data rate is ultra high (>10 Gb/s) the area of each contact becomes very small.
3. The small mechanical parts are very easily damaged.
4. The fabrication is expensive.
An alternative to metal connectors 1s a wireless signal connection. However, a wireless connection is less ideal due to electromagnetic interference (EMI) and limited frequency resource. A further promising alternative is a dielectric connector, for example U.S. Pat. No. 7,481,672. However, such prior art dielectric connectors are mainly useful for DC isolation and still suffer from EMI problems, especially in the unconnected state. EMI problems can relate to the device being overly susceptible to interference from other devices, and/or that the device causes excessive interference in other devices.
In general terms the present embodiments propose a resonant electromagnetic (EM) coupler which does not radiate significantly in an unconnected state. This may have the advantages(s) that:
1. no metal contacts are required,
2. EMI may be substantially eliminated for both connected and disconnected state,
3. consistent performance over the device lifetime,
4. longer life-time,
5. water resistant,
6. wideband >10 GHz bandwidth @centre frequency 60 GHz (or relative bandwidth>16%) and hence much higher data rate (>10 Gb/s) can be achieved,
7. no radio frequency license needed,
8. safer data transmission because there is no radiation leakage to the environment, any information transmission is point-to-point. Thus, the connection security is higher than common wireless communications where the transmission can be detected by many others besides the desired receiver, and/or
9. better looking compared with a metal cable connector and may not be visible.
In a first specific aspect there is provided an electromagnetic coupler comprising a transmitter configured to operate at a first central frequency, a first termination configured to connect to the transmitter and having a second resonant frequency, a receiver configured to operate at the first frequency, a second termination configured to connect to the receiver and having a third resonant frequency, wherein when the first and second terminations are bought into close proximity when engaged, the equivalent resonant frequency is substantially the first central frequency, and wherein the second and/or third resonant frequencies are substantially spectrally spaced from the first central frequency.
One or more example embodiments will now be described, with reference to the following figures, in which:
a) is an equivalent resonance circuit diagram and graph of frequency response of the dielectric connector in a disconnected state,
b) is an equivalent resonance circuit diagram and graph of frequency response of the dielectric connector in a connected state,
a) is a perspective view of a dielectric coupler pair according to a second embodiment,
b) is a perspective view of a Tx termination according to the second embodiment,
a) is a frequency response graph of the second embodiment in a connection state,
b) is a frequency response graph of the second embodiment in a disconnection state,
a) is a cross section of an inserting type Rx termination in a disconnected state according to a third embodiment,
b) is a cross section of an inserting type Tx termination in a disconnected state according to the third embodiment,
c) is a cross section of an inserting type connector in a connected state according to the third embodiment,
a) is a cross section of a touching type Rx termination in a disconnected state according to a fourth embodiment,
b) is a cross section of a touching type Tx termination in a disconnected state according to the fourth embodiment,
c) is a cross section of a touching type connector in a connected state according to the fourth embodiment, and
A dielectric coupler 100 is illustrated in
When the two terminations 104, 106 are disconnected, the signal will be reflected back instead of radiated into the atmosphere. When two terminations 104, 106 are connected, the couplers have just dielectric touching and the signal is transferred without any significant leakage. So whether the coupler is connected or not, there is no external RF signal radiation and the leakage may be insignificant.
The coupler is based on a resonant frequency shifting principle, which is illustrated in
a) shows a dielectric coupler according to the second embodiment. It includes a Tx termination 300 and a Rx termination 302. The Tx termination 300 is shown in
The Tx termination 300 is made on PCB material (e.g., FR408). In
The coupler performance according to the second embodiment is shown in
The slot loop and slot dipole structure of the antenna 306 shown in
The propagation loss is 1.38 dB at the central frequency in the connected state as shown in
A coupler may be modified by designing the bandwidth (e.g., 10 GHz), dielectric constant material (e.g., −11) and radiation leakage rate according to the requirements of a given application.
To further reduce any RF leakage, an absorber may surround the terminations. The absorber should have small effect to coupler parameters. Thus, less dielectric constant absorber foam or rubber is preferred. The absorbing rate should be as high as possible.
The dielectric connector can be modified according to the requirements of a given application. Three examples are introduced below.
a), 5(b) and 5(c) show an inserting type coupler 500. In
c) shows a touching type coupler 600. The Tx termination 602 and Rx termination 604 face each other. To maximise the terminations alignment, some self-alignment structure is needed. For example, with a central working frequency of 60 GHz and the dielectric constant of 10.2, then the mechanical tolerance is about ±0.1 mm to ensure good coupling. There are many kinds of self-alignment systems that can be used, such as magnetic or embossing. An absorber 606 placed under the Tx termination to further reduce the radiation leakage in the connected and disconnected states.
In the previous embodiments, the Rx resonant frequency may be fixed at the working frequency because the high dielectric constant material is permanently provided on the Rx side. To achieve two-way communications, an individual reverse connector 702 made of high dielectric constant material is provided as shown in
While example embodiments have been described in detail, many variations are possible within the scope of the disclosure as will be clear to a skilled reader.
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2012-03955-8 | May 2012 | SG | national |
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