Technical Information Rev.1 M1621B The M1621B is an electronic frequency tuning pulsed type X-band magnetron, designed to operate at 9380 to 9440 MHz with a peak output power of 4kW. The oscillation frequency is tuned by applying bias voltage to the tuning bias terminal from the customer’s control circuit board. The magnetron has a waveguide output. This magnetron only needs to be conduction cooled. A permanent magnet is packaged as part of the magnetron. GENERAL CHARACTERISTICS ----ELECTRICAL---Heater voltage (note 1) Heater current Minimum preheat time (note 2) ----MECHANICAL---Dimensions Net weight Mounting position Cooling (note 3) Output coupling 6.3V 0.55A 65sec Per outline drawing 0.44kg approximately Any direction Conduction cooling or forced air. UG-40B/U or WRJ-10 ABSOLUTE MAXIMUM RATINGS These ratings cannot necessarily be used simultaneously and no individual ratings should be exceeded. Min 5.7 3.4 2.5 Max Heater voltage 6.9 Peak anode voltage 3.9 Peak anode current (note 4, 5) 4.5 Average anode power input (note 6) 13 － Duty cycle 0.0012 － Pulse duration (note 7) 0.05 4.0 Rate of rise of voltage pulse (note 8) 55 － 1-1,Fukuoka 2-chome,Fujimino-city Saitama-pref. 356-8510 Japan 1 Units V kV A W us kV/us Phone:049-278-1298 Fax :049-278-1419 Technical Information Min Max Anode temperature (note 3) － 100 V.S.W.R. at the output coupler Tuning bias voltage (note 10) － 0 1.2:1 10 TYPICAL OPERATION Operational Conditions Heater voltage Peak anode current Pulse duration Pulse repetition rate Rate of rise of voltage pulse Typical performance Peak anode voltage Peak output power Average output power Rev.1 Units degree centigrade V Condition 1 6.3 3.0 4.0 250 35 Condition 2 6.3 3.0 1.0 1000 35 Units V A us p.p.s kV/us 3.6 4.0 4.0 3.6 4.0 4.0 kV kW W TEST CONDITIONS AND LIMITS The tube is tested to comply with the following electrical specification: Test Conditions Heater voltage (operating) Average anode current Duty cycle Pulse duration (note 7) V.S.W.R. at the output coupler Rate of voltage pulse 1-1,Fukuoka 2-chome,Fujimino-city Saitama-pref. 356-8510 Japan 2 Condition 1 6.3 3.0 0.001 4.0 1.05 Condition 2 6.3 3.0 0.001 1.0 1.05 35 35 Units V mA us kV/us min. Phone:049-278-1298 Fax :049-278-1419 Technical Information Rev.1 Limits Condition 1 Min Max 3.4 3.8 3.8 4.4 9380 9440 Condition 2 Min Max 2.5/tp － － － － 2.5/tp Units kV kW MHz MHz 23 － － MHz － － － MHz － － － － － － MHz/us － 1.1 MHz － 0.5 0.05 0.6 -0.25 Peak anode voltage Peak output power Frequency (Bias voltage =0V) R.F bandwidth at 1/4 power － Frequency pulling: － (V.S.W.R. not less than 1.5:1) Tuning frequency 20 Bias voltage = 0 to 8 V (note10) Tuning response time (increase) 0.04 (note10) (decrease) 20 Frequency repetition stability － at each bias voltage (note 9) Stability (note 11) － Heater current (note 12) Temperature coefficient of frequency (note 14) 0.05 － － － MHz/us % A MHz/ degree LIFE TEST End of Life Performance (under Test Conditions 1) The tube is deemed to have reached end of life when it fails to satisfy the following: Peak anode voltage Peak output power R.F. bandwidth at 1/4 power Frequency Stability (note 11) 3.4 to 3.9 kV 3.0 kW min 3.5/tp MHz max 9315 to 9375 MHz 0.5 ％ max NOTE: 1. No reduction of heater voltage is required. 2. For ambient temperatures from -10 degrees centigrade to +70 degrees centigrade at heater voltage between 5.7V and 6.9V. 1-1,Fukuoka 2-chome,Fujimino-city Saitama-pref. 356-8510 Japan 3 Phone:049-278-1298 Fax :049-278-1419 Technical Information Rev.1 3. The anode temperature measured at the point indicated on the outline drawing must be kept below the limit specified by means of a suitable flow of air or additional thermal radiator. The thick waveguide flange and the flange contact to the pedestal with a thick metal plate design are better for conduction cooling. 4. Any overshoot of the anode current is not acceptable. The impedance of this magnetron is similar to current production magnetrons however the transient impedance is different. This means that additional reactance should be may be required for adjusting the anode current waveform, if this magnetron will be installed into a standard modulator designed for a standard magnetron. 5. Saggy anode current should be avoided by adjusting the anode voltage pulse waveform. The flat part of anode current waveform must be kept above the anode current’s lower limit value. The flat anode current increases the Sharp Spectrum main lobe. 6. The various parameters are related by the following formula: Pi = ib × epy × Du where Pi = mean input power in watts ib = peak anode current in amperes epy = peak anode voltage in volts Du = duty cycle 7. Tolerance ±10％ 8. Defined as steepest tangent to leading edge of voltage pulse above 80％ amplitude. 1-1,Fukuoka 2-chome,Fujimino-city Saitama-pref. 356-8510 Japan 4 Phone:049-278-1298 Fax :049-278-1419 Technical Information Rev.1 9. The frequency repetition stability is measured with a frequency detector. Then the bias voltage is applied to sweep full range of the specification from 0V to 8V in a pulse duration with a saw wave form. Then install a 240 Ω resistor in series to each bias terminal. 10. A 240 Ω resistor must be installed in series to the each tuning bias terminal to avoid over current of the reactance devices. The load characteristics of each tuning bias terminal is shown in the graph on the right side. 11. The response rate for tuning the frequency lower is faster than the response rate for tuning the frequency higher. It is recommended to tune the frequency lower when using frequency modulation within a pulse. Then the rising up slope of the tuning bias voltage will be used. 12. With the tube operating into a V.S.W.R. of 1.5:1 phased to give maximum instability. Pulses are defined as missing when the r.f. energy level is less than 70％ of the normal energy level in a 0.5 ％ frequency range. Missing pulses are expressed as a percentage of the number of input pulses applied during the period of observation after a period of 5 minutes. 13. Measured with heater voltage of 6.3V and no anode input power. 14.Design test only. The maximum frequency change with anode temperature change is measured after warming. 1-1,Fukuoka 2-chome,Fujimino-city Saitama-pref. 356-8510 Japan 5 Phone:049-278-1298 Fax :049-278-1419 Technical Information Rev.1 15. It is necessary to reconfirm the spectrum, spurious emission, RF waveform, and anode voltage/current waveform if any hardware modification is made. The modification of the hardware for the modulator and the RF transmission line is critical in defining the resultant spectrum produced by the magnetron. Modification to any part of this hardware may result in change to the required spectrum and the magnetron driving characteristics which may include the overshoot of the anode current. 16. The heater lead wires should be covered with an insulator tube to avoid high voltage arcing. The high voltage limit for these lead wires is AC 1.5kV 1 minute. 17. The magnets should be kept 1’ away from any ferrous objects to avoid them from being degaussed. A non-magnetic screwdriver must be used to tighten the screw on the wave guide flange. 18. This magnetron is designed and intended to be used within each country’s radio frequency regulation. Any use outside these regulations is not authorized or approved by the manufacturer. 1-1,Fukuoka 2-chome,Fujimino-city Saitama-pref. 356-8510 Japan 6 Phone:049-278-1298 Fax :049-278-1419 Technical Information Rev.1 Performance Chart: A magnetron unstable oscillates at the low anode current condition less than 2.5A specified the absolute maximum ratings. Unstable oscillation degrades the magnetron’s performance. 1-1,Fukuoka 2-chome,Fujimino-city Saitama-pref. 356-8510 Japan 7 Phone:049-278-1298 Fax :049-278-1419 Technical Information Rev.1 Typical data: Original frequency stability T emperature Drift Aged Frequency Drift 20 Ib=3.0(A) tp=1.0(us) Duty=0.001 -5 Shift Frequency (MHz) Shift Frequency (MHz) 0 -10 -15 -20 Ib=3.0 (A) VSWR≦1.1 15 10 5 0 -5 -10 -15 -25 -20 0 2000 4000 6000 8000 -60 10000 -40 0 20 40 60 80 100 Anode T emperature (degrees Centigrade) Oscillated Time (hours) Current Pushing Characteristics Pulling Characteristics 20 Changed Frequency (MHz) 5 Changed Frequency (MHz) -20 0 -5 -10 -15 tp=1.0(us) Duty=0.001 VSWR ≦ -20 -25 VSWR =1.5 15 10 5 0 -5 -10 -15 -20 2 3 4 0 5 10 Anode Current (A) 15 20 25 30 Phase (mm) Tuning Frequency Characteristics Tuning Characteristics Changed Frequency (MHz) Changed Frequency (MHz) 0 -5 -10 -15 -20 -25 -30 Frequency Repetition Stability in a Pulse Ib=3.0(A) tp=4.0(us) 9460 Duty=0.001 Saw bias voltage Measurement ; 9455 5 pulses (max. and min.) resolutin=50 (pseconds) 9450 9445 9440 0 2 4 6 8 10 12 0 Tuning Bias Voltage (V) 1-1,Fukuoka 2-chome,Fujimino-city Saitama-pref. 356-8510 Japan 1 2 3 4 Pulse Duraion (us) 8 Phone:049-278-1298 Fax :049-278-1419 Technical Information Rev.1 1-1,Fukuoka 2-chome,Fujimino-city Saitama-pref. 356-8510 Japan 9 Phone:049-278-1298 Fax :049-278-1419