Microwave oscillator

A box-shaped metal microwave oscillator is provided having two pairs of substantially parallel, confronting inner surfaces, the second pair perpendicular to the first pair to define an oscillator cavity. The forward end of the cavity is walled off with a slotted wall to permit only a portion of the oscillator energy to be emitted. The spacing of certain of the walls and the location of the oscillator components to the wall is described.

This invention relates to microwave oscillators, and more particularly to microwaveoscillators for use in police radar warning receivers.

A police radar warning receiver is an electronic assembly mountable in a vehicle, such as a passenger car or truck, motorcycle, boat or the like, which travels on land or water in areas subject to speed-monitoring radar surveillance by police,and functions to detect the presence of the police radar and provide the driver or user with an audible and/or visual indication that his speed is being checked by radar.

Typically, a police radar warning receiver includes an antenna, a printed circuit board, the circuitry needed to determine whether the received signal is a police radar signal and to provide appropriate indications and alarms, and a powerregulator device which regulates the energy received from a vehicle battery to power the circuitry. These components are located within a box-like housing having four side walls and front and rear end panels. The front panel which, when the receiver ismounted in the vehicle, faces the user, has indicators and control knobs. The rear wall has extending from it a power cord terminating in an appropriately configured plug to be received into the vehicle cigarette lighter.

Police radar units operate in either the X-band or the K-band of the frequency spectrum, as discussed in U.S. Pat. No. 4,313,216. Typical radar warning receivers are adapted to detect police radar signals in either band. Accordingly, policeradar warning receivers are sometimes referred to as dual frequency radar warning receivers.

One illustrative form of prior art receiver is the ESCORT radar warning receiver currently marketed by the assignee herein, Cincinnati Microwave Inc. of Cincinnati, Ohio. The ESCORT radar warning receiver contains circuitry permitting it todetect and indicate the presence of both X-band and K-band police radar signals. That circuitry is disclosed in aforesaid U.S. Pat. No. 4,313,216. Briefly, the oscillator generates dual frequency signals which are quasi-harmonically related. Thesesignals mix with the incoming signal and provide an output or mixed signal (the IF). The IF signal is evaluated to determine whether a police radar signal is present in which case an alarm is activated. This process is referred to as heterodyning, orsuper-heterodyning where the IF is mixed again with another local oscillator signal before evaluation.

Improved versions of the circuitry disclosed in U.S. Pat. No. 4,313,216 are described in U.S. patent application Ser. No. 575,422, filed Jan. 31, 1984, and U.S. patent application Ser. No. 656,026 entitled "Police Radar Warning ReceiverWith Mute Function," invented by Richard L. Grimsley, and filed concurrently herewith. Both of the aforesaid patent applications are also assigned to Cincinnati Microwave, Inc.

Police radar warning receivers of the heterodyne or super-heterodyne type utilize a microwave oscillator. Accordingly, an object of the present invention has been to provide an improved microwave oscillator for use in a police radar warningreceiver.

That objective has been achieved by providing a box-shaped oscillator section having a first pair of substantially parallel, confronting inner surfaces and a second pair of substantially parallel, confronting inner surfaces, the latter beingperpendicular to the former to define an oscillator cavity. The oscillator also has a slotted wall perpendicular to the four inner surfaces and positioned at one end of the oscillator section to preferentially permit only a portion of the oscillatorgenerated microwave signals to pass out of the oscillator cavity, whereby oscillation can be maintained in the oscillator cavity.

The oscillator further includes a Gunn diode having a central axis and being mounted within the oscillator cavity. The Gunn diode central axis is equidistant from both the second pair of inner surfaces and is spaced rearwardly of the slottedwall a predetermined distance L. The second pair of inner surfaces are spaced apart a predetermined distance W as determined by the formula: ##EQU1## wherein C=velocity of light;

L>W; and

12.0 Ghz

Other References

• Reference Data for Radio Engineers--p. 23-19
• Foundations for Microwave Engineering, pp. 322-323
• "Proven Procedures Guide Cavity VCO Design" Microwave (May, 1981)
• Microwave Engineer's Handbook, p. 26
• Foundations for Microwave Engineering, p. 96

Integrated multilayered microwave circuit

The present invention generally relates to integrated multi-layered microwave circuits used in a mobile radio communication system utilizing a radio wave of a microwave band such as a vehicle information and communication systems (VICS) and, more particularly, is directed to an integrated multi-layered microwave circuit and a method of fabricating it which is easily miniaturized and has less signal loss.
In the VICS, a vehicle antenna receives various information such as a location of a vehicle or a road condition such as congestion which is transmitted from a terrestrial station such as a beacon provided on a road, and various devices mounted on the vehicle are controlled based on the received information. Further, it has been proposed to arrange the VICS so that the vehicle antenna transmits information from the various devices mounted on the vehicle to an external station such as the earth station or another vehicle. The thus constituted VICS has been put to practical use as an example of the mobile radio communication systems utilizing a radio wave of a microwave band. In particular, it has been an important problem to be solved to miniaturize and decrease weight in a radio communication terminal for a mobile station which is mounted in a movable body (mobile) or vehicle and processes a signal received by a vehicle antenna.

In a conventional circuit arrangement usable as the radio communication terminal for the mobile station of the mobile radio communication system, an antenna portion and a communication portion for processing a signal received by the antenna portion are provided separately, in general, in order to freely position the antenna portion. That is, in almost cases, the antenna portion and the communication portion are located at different portions. For example, in the prior art disclosed in JP-A-2-152304, an antenna for a mobile radio communication and a communication portion are located at different portions and are connected to each other through a coaxial cable.

Further, there has been proposed various circuits in each of which an antenna for a mobile communication for receiving a radio wave of a microwave band is constituted by a micro strip line and integrated with a communication portion for processing the received signal. One is a circuit in which an antenna portion and an integrated circuit constituting a communication portion are separately fabricated and then integrated as described in JP-A-63-316905. Another is a circuit in which an antenna constituted by a micro strip line and a communication portion constituted by a semiconductor circuit are formed on the same major surface of a substrate as described in JP-A-1-112827.

In the circuit described in JP-A-2-152304, since the coaxial cable is used to connect the antenna for the mobile communication and the communication portion, a radio frequency (RF) signal is attenuated due to a signal loss in the coaxial cable, thereby an efficiency of the communication portion degrades.

Further, the circuit described in JP-A-63-316905 has the disadvantage such that, since material of the communication portion, i.e., semiconductor material is different from material of the antenna portion, i.e., conductive material, it is required, in an integrating process of the materials, to provide a conductive layer at a rear surface of the communication portion and to-utilize an adhesive solder, thereby complicating an assembling process of the circuit.
The circuit described in JP-A-1-112827 is advantageous in that signal loss of an RF signal can be decreased and the circuit can be miniaturized and light-weighted since the antenna and the communication portion are integrally formed. However, this circuit has the disadvantage such that since both the antenna and the communication portion are located on the same surface, a radio wave having the same frequency of that from the antenna is transmitted from the communication portion and interferes with a radio wave transmitted from the antenna, so that this circuit can not be applied to one whose communication portion has a modulating function.

Accordingly, it is an object of the present invention to provide an improved integrated multi-layered microwave circuit in which the aforementioned shortcomings and disadvantages encountered with the prior art can be eliminated.

More specifically, it is an object of the present invention to provide an integrated multi-layered microwave circuit which can integrate an antenna portion and a communication portion by using a conventional fabricating process of a circuit substrate and which is small in size and weight, less in signal loss and high in efficiency.

Evolvable Microwave Circuit

Microwave circuits are indispensable for mobile and multimedia communication. However, these circuits are very difficult to design, because of the nature of distributed-constant circuits in the microwave range (i.e., over 1 GHz). These circuits are also difficult to adjust for optimum performance, even for experienced engineers. These related problems make development costs of microwave circuits very high. In order to overcome these problems, we propose an EHW-based microwave circuit where performance adjustment is carried out automatically by a GA. This new approach of integrating a performance adjustment function within the circuit eliminates many of the design problems with associated these circuits. In this paper, we present an EHW-based image-rejection mixer circuit, which we have developed with this approach, and experimental data that demonstrates that the automatically adjusting circuit is capable of outperforming a circuit adjusted by an experienced engineer.

RF LDMOS power transistor -> efficiency bar

Designed to set new standards for RF performance in ISM markets, Freescale
Semiconductor’s RF division has further pushed the power limits of LDMOS RF power transistors. Unveiled at the MTT-S International Microwave Symposium in Honolulu, Hawaii, the MRF6VP11KH delivers pulsed-RF output power of 1 kW at 130 MHz with higher drain efficiency and power gain. Pulse width is 100 s, duty cycle is 20% and powergain is rated 27 dB.
Operating at 50 V, the LDMOS provides designers of high-power systems such as magnetic resonance imaging (MRI) systems, CO2 lasers, plasma generators and other systems with significant benefits when compared to bipolar and MOSFET devices.
According to Freescale, the high gain at an unprecedented power level drastically reduces the number of parts required vs. traditional designs. This enables designers to significantly reduce board space requirements
and manufacturing complexity. Crafted for operation from 10 MHz to 150
MHz, the transistor leverages Freescale’s sixth-generation, very high-voltage (VHV6) LDMOS technology. “In delivering the MRF6VP11KH, we
have set industry benchmarks in efficiency, output power, reliability, and ease of design integration,” said Gavin P. Woods, vice president and general manager of Freescale’s RF division. “No other RF power device, whether LDMOS, MOSFET, or bipolar, can claim this achievement. We will continue to introduce ground-breaking devices for this marketplace, enabling our customers to break new barriers in system performance.”
The part delivers 65% drain efficiency, an exceptionally high value for any type of RF power device, said Freescale. When combined with gain of more than 27 dB, this level of efficiency makes it possible to dramatically reduce amplifier design complexity, gain stages, parts count, and circuit board real estate, said the maker.
An application requiring 2 kW pulsed output power and 45 dB of gain typically requires a 15 W pre-driver, two 15 W drivers, and eight final amplifiers when using MOSFETs or bipolar devices—a total of three stages and 11 devices. By comparison, stated Freescale, a design based on the new high voltage LDMOS transistor requires only three devices: a single 10 W LDMOS driver and two MRF6VP11KH final amplifiers, to produce the same output power and a highe
gain of 50 dB.
In addition, the 50 V bias voltage employed by the MRF6VP11KH produces higher terminal impedances for a given power level, which makes the device easier to match into an amplifier circuit. The thermal resistance of Freescale’s RoHS compliant, air-cavity ceramic package was measured at less than 0.13 oC/W θJC, providing efficient thermal management and reducing heat sink size.
Plus, it incorporates an integrated electrostatic discharge (ESD) protection eliminating the need for special handling procedures beyond those routinely observed in electronics manufacturing.
Samples of the MRF6VP11KH and a supporting reference design are available with production expected to begin in the fourth quarter.
For more information, visit www.freescale.
com.

20dB VHF Amplifier

Many times we needed to strengthen a small signal in the region of VHF or FM, or it is we lead a body, or a receptor. The preamplifier that to you we propose offers 20dB in all the region of VHF and it still can reach also their 500MHZ.

The amplifier is a circuit of high frequency RF with distinguishable materials. The amplifier as circuit strengthens the tendency of signal with concrete aid, depending on the frequency of signal. If the frequency of signal is included in the limits of spectrum of frequencies of amplifier, then it is strengthened, otherwise it is downgraded. Each amplifier of this category, accordingly with his designing, strengthens a concrete region of frequencies and obeys in same characteristics. The one that to you we present today concerns the regions of VHF where they exist and the corresponding television stations for channels 5 until 12. His circuit he is enough simple, so that it is made easily with materials that exist in the trade. It is based on transistors with aid until the 500MHZ. The type of transistor can be BF197 or some other.

Theoretical circuit

In form 1 appears the theoretical circuit of amplifier. As we see it is constituted from two similar circuits (rungs). In this circuits are not included in joint action circuits. With that way is covered a wide spectrum of frequencies, without is differentiated abruptly the aid as for the frequency. With this provision we have smaller gain but big breadth of frequencies. The two rungs are same, with the same prices of materials and each rung offer aid roughly 10dB. The transistors and the remainder materials, because the industrial manufacture, have almost the same characteristics. Associates the particular characteristics of demagogues are altered mainly the aid of rung. Each rung uses a transistor of type npn in provision of common emitter that functions in order A. his rungs works in provision of common emitter with null resistance in emitter. In each rung a network of resistances between the collectors and the bases polarize the transistors and ensures the operation of circuit. The junction between the rungs becomes via ceramic capacitors of small capacity from 0,1nF until 0,22nF (at preference ceramic). In the place of two rungs we can try various transistors of independent company or even different between them. The circuit of course cannot work with all of them. The tendency of catering should emanate from stabilised power supply with tendency 12V. Depending on the tendency of catering and the type of transistor, in each rung of amplifier it needs enter also different resistances. Force of expense, under conditions of high excitation it can exceed the 1 mW

Manufacture

The total aid of circuit, according to the elements of transistors, reaches 20dB. Enough aid for a lot of applications. The amplifier is drawn in order to it has big response of frequency up to 0,5Ghz. According to the particular characteristics of manufacture, the better application that we could to you propose for this designing would be the aid of television signal emanating from a small transmitter of television or the preamplifier of a frequency meter. The assembly of amplifier is realised above in printing form 2. In this you will place all the materials according to form 3. The manufacture, in order to it works right it needs one small stabilised power supply 12V. The consumption of circuit is small hardly some mA. The resistance en line with the collector is 10 000. When you finish the construction and the control of manufacture, place the PCB in metal box of suitable dimensions.

PARTS

R1 = 1K	C3 = 120pF
R2 = 47K	C4 = 150pF
R3 = 1K	C5 = 0,1uF
R4 = 47K	C6 = 120pF
C1 = 150pF	C7 = 150pF
C2 = 0,1uF	Q1 = Q2 = BF197

VHF Video Transmitter

This circuit is a powerful video sender in VHF band. The modulator section is designed to operate on either channels 7 to 13 or 14 to 29. For channels 7 to 13, L1 and L2 are 3 turns of #22 wire wound on a 3/16 inch form. For channels 14 to 29, L1 and L2 are 2 turns of #22 wire wound on a 3/16 inch form. Video signal is modulated as AM.

1.5V FM Transmitter

Operates from 87-109MHz. The current draw for this tracker is 3.7mA, so the 1.5V button cell will last a while. There is an experimental version that was tuned to 87.6MHz and worked as expected on only 1.5 volts.

When your circuit is working you should see the LED flash quite fast. Take your FM radio and search for the low-beat ‘thumpe-thumpe-thumpe-etc’ equal to the flash of the LED (probably around the 100Mhz). Found it? If that position is interfering with a radio station you can fine-tune it with the variable capacitor. If you like to have the tracker around the 88Mhz (or lower) you can do that by keeping the windings from the home-made coil close together. Anyways, play with it and learn. It may take alot of patience to find the signal but once you know where it is it becomes simple. It is a nice learning project.

White OLED surpasses fluorescent lamp efficiency

Cristopher Hammerschmidt published this week surprising news about OLED!

The Dresden technical university and OLED vendor Novaled AG (Dresden, Germany) claim they have reached an efficiency of 90 lumen per watt. Now researchers have to overcome only lifetime issues to trigger the breakthrough to general lighting applications with OLEDs. Hitherto, fluorescent tubes were the most efficient sources for white light in general lighting applications, offering efficiencies between 50 and 70 lumen per watt, if equipped with reflectors and similar efficiency-increasing measures. Now the team of Novaled and the Institute of Applied Photophysics (IAPP) of the Dresden technical university significantly surpassed this mark with 90 lm/W at a brightness of 1.000cd per square meter (as a comparison, an average computer screen offers a brightness of 300 cd per square meter). By applying systems to couple out the light, the efficiency can be increased to 124 lm/W. Even at a very high brightness of 5.000 cd per square meter the scientists could reach an efficiency of 74 lm/W. The results were achieved with what the researchers called an "application relevant" component using Novaled's PIN doping technology. The next issue for scientists will be the lifetime of the light sources. Novaled says it already has achieved devices with operating times of 100.000 hours and beyond albeit at lower efficiency. Another challenge will be the transfer to volume production. Novaled hopes the commercial production of OLED lamps could start in the 2009/2010 time frame. As opposed to other light sources, OLED lamps can be formed in just about any shape and typically will be implemented as large two-dimensional foils. Courtesy of EE Times Europe

Baring RF devices: Analog Office

http://www.awr.tv/Product-Videos/Analog-Office-Videos/

Analog Office

The Analog Office® design suite is a modern and complete design system that is specifically architected and optimized from the ground up for analog and radio-frequency integrated circuit (RFIC) designs. Analog Office software leverages AWR's unique unified data model to provide designers with a concurrent, interconnect-driven and RF-aware design methodology for RFIC and module design. The fundamental data models within the software are high-frequency aware, permitting accurate extraction and modeling of all design elements, including active and passive devices, as well as interconnect, at high-frequency.