Frequency multiplier for millimeter waves having means for adjusting harmonic frequency

• US 4,636,758 A
• Filed: 01/16/1985
• Issued: 01/13/1987
• Est. Priority Date: 01/27/1984
• Status: Expired due to Fees

• Current Assignee: Alcatel Thomson Faisceaux Herziens
• Original Assignee: Alcatel Thomson Faisceaux Herziens
• Inventors: Mettoudi, Isaac
• Primary Examiner(s): LaRoche, Eugene R.
• Assistant Examiner(s): Lee, Benny
• Application Number:
  US06/692,051
• Time in Patent Office: 727 Days
• Field of Search: 333/218, 333/250, 331/96, 331/107 DP, 331/107 C, 363/157, 363/158, 363/159, 329/160-162
• US Class Current: 333/218
• CPC Class Codes: H03B 19/18 and elements comprising distributed inductance and capacitance

Abstract

A frequency multiplier according to the invention comprises a coaxial input, an elastic device constituted by two parts sliding within one another, the outer part having a flexible metal bellows and which is extended by a spring, an impedance matching low pass filter requiring no setting, an IMPATT VARISELF diode, a coaxial line, a waveguide transition regulating plunger, a waveguide, a diode holder whose position is regulatable in translation by a button, a cavity tuned to a harmonic frequency, a mobile short-circuit closing the cavity and which is regulatable in translation by means of a knurled wheel in order to adjust the resonant frequency of the cavity to a harmonic frequency and a pin screw immobilizing in rotation the diode holder and the mobile short-circuit.

Claims

1. A frequency multiplier for millimeter waves comprising:

a coaxial input, having a central conductor connection an an outer conductor connection, for receiving an incident signal, the frequency of which is to be multiplied;

a low-pass filter of the impedance transformer type for filtering and impedance matching, having a filter input and a filter output, said filter input being coupled to said coaxial input and having a pass-band exceeding said frequency to be multiplied and less than a predetermined maximum value of multiplied frequency;

a rectangular waveguide having a pair of greater sides and a pair of lesser sides and having a first end constituting an output of said multiplier and a second end at least partially closed by a short-circuiting piston;

a cylindrical cavity located in a first one of said greater sides of said wave guide, having a cylindrical wall and having an axis perpendicular to said greater wave guide sides, said axis lying in a median plane of said wave guide parallel to said 1esser sides thereof;

a semiconductor diode located on said axis;

an elongate diode carrier for said diode coaxially disposed within said cavity and to which one terminal of said diode is connected, said diode having a second terminal connected with said filter output connection of said impedance transforming low-pass filter, said filter output connecting being seated in an orifice centered on said axis and provided in a second one of said greater wave guide sides;

means for setting said diode carrier in an adjustable position on said axis, said setting means including a rotary control for adjusting said position along said axis;

means for preventing said diode carrier from rotating about said axis during operation of said rotary position control

an annular piston coaxially located between said diode carrier and the cylindrical wall of said cavity and slidably mounted for displacement in axial direction for tuning said cavity at a desired multiple of said incident signal frequency, said diode carrier having a cylindrical outer surface over a length of said carrier leading away from said diode for accommodating a sliding movement of said annular piston, said annular piston being provided with means for preventing rotation of said piston about said axis and means for adjusting the position of said piston in the axial direction, and having at its extremity nearer to said wave guide, inner and outer flexible crowns split in radial planes by slots to assure circumferential distribution of sliding contact pressure, said inner flexible crown providing for axially sliding contact with said diode carrier and said outer crown providing for axially sliding contact with said cavity wall and

a lengthwise-elastic connecting device for connecting said center conductor connection of said coaxial input to said filter input regardless of any axial adjustment of the position of said diode while maintaining substantially constant impedance for microwave transmission along its length, said connecting device incorporating a bellows for length variation, being at least partly hollow and having therewithin a helical spring urging length extension of said device.

2. Frequency multiplier according to claim 1, wherein said means for adjusting the position of said diode carrier axially comprise a knurled knob centered on said axis and mounted on screw threads for propelling said diode carrier along said axis by rotation of said knob, said knob being connected to said diode carrier at the end of said diode carrier remote from said diode for imparting axial motion to said diode carrier without requiring said diode carrier to rotate about said axis and wherein said means for preventing rotation of said diode carrier comprise an axially elongated slot traversing said diode carrier and a rotation-restraining pin passing through and fitting into said slot and mounted across said cylindrical cavity.

3. A frequency multiplier for millimeter waves comprising:

a coaxial input, having a central conductor connection and an outer conductor connection, for receiving an incident signal, the frequency of which is to be multiplied;

a low-pass filter of the impedance transformer type for filtering and impedance matching, having a filter input and a filter output, said filter input being coupled to said coaxial input and having a pass-band exceeding said frequency to be multiplied and less than a predetermined maximum value of multiplied frequency;

a rectangular waveguide having a pair of greater sides and a pair of lesser sides and having a first end constituting an output of said multiplier and a second end at least partially closed by a short-circuiting piston;

a cylindrical cavity located in a first one of said greater sides of said wave guide, having a cylindrical wall and having an axis perpendicular to said greater wave guide sides, said axis lying in a median plane of said wave guide parallel to said lesser sides thereof;

a semiconductor diode located on said axis;

an elongate diode carrier for said diode coaxially disposed within said cavity and to which one terminal of said diode is connected, said diode having a second terminal connected with said output connection of said impedance transforming low-pass filter, said output connection being seated in an orifice centered on said axis and provided in a second one of said greater wave guide sides;

means for adjusting and setting the position of said diode carrier axially, comprising a knurled knob centered on said axis and mounted on screw threads for propelling said diode carrier along said axis by rotation of said knob, said knob being connected to said diode carrier at the end of said diode carrier remote from said diode for imparting axial motion to said diode carrier without requiring said diode carrier to rotate about said axis;

means for preventing rotation of said diode carrier comprising an axially elongated slot traversing said diode carrier and a rotation-restraining pin passing through and fitting into said slot and mounted across said cylindrical cavity;

an annular piston slidably mounted for axial displacement in said cavity between said diode carrier and the cylindrical wall of said cavity for tuning said cavity at a desired multiple of said incident signal frequency, said diode carrier having a cylindrical outer surface over a length of said carrier leading away from said diode for accommodating a sliding movement of said annular piston, said annular piston being provided with means for preventing rotation of said piston about said axis;

means for axially adjusting the position of said annular piston comprising a hollow cylinder of circular cross-section located coaxially between said diode carrier and said wall of said cavity, connected at one end to said annular piston and extending therefrom in the axial direction away from said diode, said hollow cylinder having external screw threading for propelling said cylinder axially in response to rotary motion, and an internally threaded ring engaging said external threads of said hollow cylinder and held rotatably in said wall of said cylindrical cavity in a manner permitting the rotation of, while preventing axial displacement of, said ring and means for at least manually rotating said internally threaded ring from the outside of said cylindrical cavity wall,

said means for preventing rotation of said piston comprising longitudinal slots in said hollow cylinder diametrically opposite each other for passage of said rotation-restraining pin and for thereby preventing rotation of said hollow cylinder about said axis while permitting axial displacement of said hollow cylinder,

said means for axially adjusting the position of said piston having at its extremity nearer to said wave guide, inner and outer flexible crowns, said inner flexible crown providing for sliding contact with said diode carrier and said outer crown providing for sliding contact with said cavity wall; and

a lengthwise-elastic connecting device for connecting said center conductor connection of said coaxial input to said filter input regardless of any axial adjustment of the position of said diode.

4. A frequency multiplier for millimeter waves comprising:

a coaxial input, having a central conductor connection and an outer conductor connection, for receiving an incident signal, the frequency of which is to be multiplied, said outer conductor coaxial input connection being connected by a tubular member with an outer sleeve forming part of said filter;

a low-pass filter of the impedance transformer type for filtering and impedance matching, having a filter input and a filter output, said filter input being coupled to said coaxial input and having a pass-band exceeding said frequency to be multiplied and less than a predetermined maximum value of multiplied frequency;

a rectangular waveguide having a pair of greater sides and a pair of lesser sides and having a first end constituting an output of said multiplier and a second end at least partially closed by a short-circuiting piston,

a cylindrical cavity located in a first one of said greater sides of said wave guide, having a cylindrical wall and having an axis perpendicular to said greater wave guide sides, said axis lying in a median plane of said wave guide;

a semiconductor diode located on said axis;

an elongate diode carrier for said diode centered on said axis of said cavity and to which one terminal of said diode is connected, said diode having a second terminal connected with said output connection of said impedance transforming low-pass filter, said filter output connection being seated in an orifice centered on said axis, provided in a second one of said greater wave guide sides;

means for setting said diode carrier in an adjustable position on said axis, said setting means including a rotary control for adjusting said position on said axis;

means for preventing said diode carrier from rotating about said axis during operation of said rotary position control;

an annular piston slidably mounted for axial displacement in said cavity between said diode carrier and the cylindrical wall of said cavity for tuning said cavity at a desired multiple of said incident signal frequency, said diode carrier having a cylindrical outer surface over a length of said carrier leading away from said diode for accommodating a sliding movement of said annular piston, said annular piston being provided with means for preventing rotation of said piston about said axis and means for adjusting the position of said piston in the axial direction, and having at its extremity nearer to said wave guide, inner and outer flexible crowns, said inner flexible crown providing for sliding contact with said diode carrier and said outer crown providing for sliding contact with said cavity wall, and

a length-wise elastic connecting device for connecting said coaxial input central conductor connection to said filter input regardless of any axial adjustment of the position of said diode, which device is of a design that presents, at said filter input, a constant impedance having a magnitude of substantially 50 ohms and comprises first and second parts of both having an axis of rotational symmetry coinciding with said axis of said cylindrical cavity, said first part being shaped and disposed for telescoping on the exterior of said second part, an end portion of said first part being firmly connected to said central conductor connection of said coaxial input and a second end portion of said first part being firmly connected with the input end of said impedance transforming filter, a cylindrical conducting bellows being provided between said end portion of said first part for connecting said two end portions electrically together regardless of the spacing of said end portions from each other within a predetermined range, said second part being rigid and firmly connected to said central conductor connection of said coaxial input and having cylindrical portions respectively for axially guiding said bellows and for guiding said second end portion of said first part for maintaining the end portions of said first part in alignment, said elastic connecting device further comprising a helical spring located in an interior hollow region of said second end portion of said first part and having an axis coincident with said axis of symmetry of said first part, in a manner butting on an interal shoudler of said first part and exerting a force tending to spread apart said first and second portions of said first part and thereby to displace said impedance transforming filter along said axis for maintaining said output of said filter in contact with said second terminal of said diode regardless of the axial position of said diode holder.