CTT Technical Proposal

Transcription

1 CTT Technical Proposal 6-1 GHz 0 W Power Amplifier (GaAs and GaN approaches) SECTION 1: 6-1 GHz 0 W power amplifiers A) Specification and comparison SECTION 2: GaAs 6-1 GHz Solid State Power Amplifier Design approach A) CTT standard 10 W Power Amplifier Basic Structure B) Power Modules lineup C) 0 W GaAs 6-1 GHz amplifier (Option 1) SECTION 3: GaN 6-1 GHz 0 W amplifier (option 2) SECTION : DELAY, TTL CONTROL CIRCUIT AND HEAT SINK A) Negative DC to DC converter, delay and protection circuit B) Option for TTL on/off control to save power consumption C) Heat sink SECTION : CTT Power Amplifiers A) 1-2 GHz and 2- GHz 10 to 20 W power amplifiers B) X and Ku band 10 to 0 W pulsed power amplifier C) X band 0 W pulsed power amplifier with DC-DC converter D) Test data for GaAs 6-1 GHz 3 W power module E) Test data for CTT 6-1 GHz 10 W power amplifier F) Data for GaN 6-1 GHz MMIC 1

2 SECTION 1: 6-1 GHz 0 W power amplifiers CTT offers 2 different options for these 6-1 GHz power amplifiers. The first option is a GaAs version and the second option is GaN version. The GaAs amplifiers are designed for CW operation from 0 to +^C. The GaN amplifiers can work up to +^C. A) Specification No Description CTT Model No Frequency Gain, db, Min Gain Flatness, Max N. F., db, Max P1dB, Min Psat, Min VSWR, Max DC volts DC current Connectors Outline Size Case temperature GaAs 30-0 W Option 1 GaN 0 W Option GHz +-2. db.0 + dbm + dbm, Min +6 dbm, Typ. 2:1 + V 0 A typ. SMA, F 6-1 GHz +-2. db.0 ASM/ AGM/ TBD 0 to +^C +. dbm, Min dbm, Typ. 2:1 +36 V 6.6 A typ. SMA, F PQX.1x3.0x0.6 0 to +^C Note 1 Note 2 Note 1: CTT has made many 6-1 GHz 10 W amplifiers before. We will combine four of these amplifiers to get 30 to 0 W output power (option 1). Since the efficiency is low, the size will be big. Due to the insertion loss of the wide band power combiner, the output power at band edge (6 and 1 GHz) may fall down to 30 W (+. dbm). The current is very high (0A) that may create problem to assemble this amplifier. Many DC pin or a special high current DC connector is needed. Note 2: Option 2 uses the newest GaN MMIC for the last two stages. The driver stages will be GaAs devices. This amplifier design has good efficiency, high operating temperature range, small size, and low cost. But it is not linear. If intermodulation is not an issue, then this is a good choice. 2

3 SECTION 2: GaAs 0 W Power Amplifier Design Approach CTT s GaAs FET power amplifiers have replaced many TWTAs in the military and telecommunication markets, offering better MTBF, small size, and easier maintenance. The MTBF of our amplifiers are to 10 times better than the TWTA. If power supply is also considered, then the difference becomes even bigger. We are the major amplifier supplier for Northrop (EA1B), Lockheed (DDX), Raytheon (Patriot), L3Com (Hawk link and CDL) and AAI (UAV). We have supplied, 10, 20, 0, 0, 100 and 200 W power amplifiers (CW and pulsed) to the US Navy, Army and Air Force. These units have been used on radar, ship, data link, missile, airplane, UAV, and helicopter platforms. We have also shipped 0 W, 0 W, 0 W and 100 W X-band power amplifiers to SELEX (pulsed) over the last years. We are very proud of our state-of-the-art technology, reliability, service, and commitment. CTT has worked on GaAs power amplifiers for over 2 years. GaAs FETs are a good choice for power amplifiers below GHz and less than 0 W output power. CTT shipped thousands of solid-state power amplifiers last year. It has proven technology, availability and reliability. The linearity is also good (Ip3 roughly to 10 db above P1dB), making it well suited for communication applications. However, the break down voltage is low (1 V), and the bias for the power FETs is. to 10 V. Once the output power exceeds 0 W CW, the bias current becomes very big (over 0 A sometimes) requiring a large DC wire that poses assembly problems. GaN is a new device, which offers good efficiency, power density, and higher junction temperature. However, bad linearity, lack of availability at high frequencies, and export license issues have played a major role in delaying its popularity. This condition is changing rapidly and GaN power amplifiers will become more mature and affordable in the future. CTT is quoting a GaN version from 6 to 1 GHz as option 2. The bias voltage for the device is +3 V. SECTION 2A: 10 W GaAs Amplifier Basic Structure Since the 0 W power amplifier is really combined by four 10 W CTT standard amplifiers, we will discuss this 10 W amplifier first. CTT has worked on the thin film modules since 193. Our MIC thin film modules are designed to obtain higher output power, better VSWR, and wider bandwidth. These thin film modules are eutechtically attached to metal carriers and mechanically mounted to the aluminum housings. Many 6-1 GHZ LNA and power amplifiers have been designed, produced, and shipped to various military programs with proven record. 3

4 SECTION 2B: Power modules Up This 10 W power amplifier contains gain stages, three power combiners and one power stage. Four standard GaAs 3 W (P1dB) modules are combined to form the last stage. Module Gain P1dB Psat DC V Current 1 A1 2 A A3 1 A -1 A -1 2way. 6 A6 1 A 2Wx2.2 A + dbm 1. Negative DC-DC converter + Delay Regulator A1 A A2 A3 +1dBm A6 9 A9 2 wayx2 A 10 A10 2way Total dbm. A A A9&A10 A +1 dbm 3W x SECTION 2C: 0 W, GaAs 6-1 GHz POWER AMPLIFIER (option 1) CTT will combine four of the 10 W power amplifiers together to get this 30-0 W power amplifier. Due to the insertion loss of the power combiner and transmission line, the output power will have 1 db loss (0+6-1= ). The combined power will be around 30 W at band edge and 0 W at band center.

5 SECTION 3: GaN 0 W POWER AMPLIFIER (Option 2) This design uses the same GaN devices for the last two stages. The lineup consists of two GaAs front stages, a 3 W GaAs driver, one GaN 11 W driver, and four GaN power devices for the last stage. This amplifier will have more than 0 db gain and 0 W saturated output power. The only concern is that the output power may roll off a little bit at 6 and 1 GHz (band edge) due to the combiner loss. Since it is a GaN design, the output gain and power are not linear. It has a soft curve from P1dB to Psat. The unit is hermetically sealed and is designed to meet MIL-STD-3 requirement. The size can be CTT s standard enclosure PQX (.1x3.0x0.6 inches). It may be too small to dissipate heat. CTT may modify it to a larger housing, but the size is still times smaller than the GaAs version. This amplifier has good efficiency, high operating temperature (up to +^C); and lower cost than the GaAs version. The price may be dropped further down next year, because more devices from different vendors will be available at that time. Even though Ip3 is not good, CTT still feels that it is a good alternative to replace TWTA for jammer, radar, and other applications when linearity is not critical. Module Gain P1dB Psat DC V Current 1 A1 3 2 A A3 1 A A to10 V DCDC converter + Regulator A1 +1 dbm 6 A6 2 way A -. 2Wx2 Negative DC-DC converter + Delay A2 A3 A +1 dbm +33 dbm A 1dBm* 3.A 9 A9 2 wayx2 10 A10 2way Total dbm 6.6 A A6& A A A +1 dbm 11W x A9 & A10

6 SECTION : DELAY, TTL CONTROL CIRCUIT AND HEAT SINK Section A: Negative DC to DC converter, delay and protection circuit Both of the high power GaAs FETs and GaN devices (2 W and above) need dual voltage for the bias. The gate is biased with negative voltage and the drain is biased with positive voltage. The gate needs to be turned on earlier than the drain and vice versa when it is turned off. A delay circuit is thus necessary to make sure that the proper turn on/off sequence happens. Otherwise, the devices may be damaged. The TTL control and protection circuit can be combined into one circuit board. They are installed close to the power FETs, so the delay time can be reduced. This circuit has been designed and applied to many of CTT s standard power amplifiers. The only difference for GaAs and GaN devices is the bias voltage. GaAs uses. to 10 V, and GaN uses +2, 36 or V. If the customer has only one positive voltage, such as + V or +36 V (or +2 V), then CTT will add a negative voltage DC-DC converter to convert the positive voltage to V, and then regulated to V. This V will supply to the gate. The only issue for this negative voltage is that it creates a low frequency (<200 KHz) spurious that may affect the system performance. If the customer can supply us a V or V with 100 ma current, then we can use it for the delay circuit to protect the power FETs. The system will be much cleaner, allowing it to pass EMI test much easier. Section B: Option for TTL on/off control to save power consumption CTT has supplied many power amplifiers with a TTL on/off option. If CW mode is not necessary, then the DC current can be turned on/off by a TTL signal to save the total power consumption when duty cycle is off. During this time, the amplifier consumes 200 ma for the TTL circuit (may be a little bit more), delay, and protection circuit. Once TTL is on, the rise time plus delay time can be 10 nano seconds, and the fall time plus delay time may be 10 to 200 nano seconds. It will be fast enough for most radar application. The power consumption can be reduced 0%, if the duty cycle is around to 0%. This is good way to reduce the heat sink, power supply, and overall power consumption. This circuit, however, may create a big pulse on the DC line when TTL is on. A bigger capacitor and/or LC filter may be needed on the DC line to reduce the interference to the whole system. 6

7 Section C: HEAT SINK The power amplifier consumes 0 A * V = 600 W for option 1, GaAs power amplifier; and 36*6.6 = 23 W for option 2, GaN power amplifier. Even though the GaN amplifier consumes 0% of the power consumed by the GaAs amplifier, it is also ¼ of the size. This means that both amplifiers will get very hot, requiring heat sinks to keep the case temperatures below their maximum value. Otherwise, the junction temperature of the power devices will go up and may exceed the preferred temperature. Keeping the junction temperature of the devices below +10^C is the design guideline for GaAs devices. In order to meet this guideline, the maximum case temperature for the option 1 GaAs amplifier is +^C. GaN devices can use up to +1^C junction temperature. In order to meet this guideline, the maximum case temperature of this amplifier must be below +^C. A heat sink is still needed to keep the temperature low. Please keep in mind that a 10 degree C temperature drop may double the life time of the amplifier. To have a good heat sink with forced air will improve the MTBF of the whole amplifier. SECTION 6: CTT s power Amplifiers A) 1-2 GHz and 2- GHz 10 to 20 W power amplifiers Shipped more than 1,000 pieces.

8 B) X and Ku band 10 to 0 W pulsed power amplifier We have shipped many X and Ku band 10 W, 20 W and 0 W pulsed power amplifiers in the past. A picture of a similar amplifier is shown below and the specification can be found in CTT s catalog or website. C) X and 0 W pulsed power amplifier with DC-DC converter CTT has developed this X band 0 W pulsed power amplifier. A built in DC-DC converter converts the voltage from +2 V to +11 V.

9 D) Test data for CTT s standard 6-1 GHz 3 W power module 9

10 E) Test data for CTT 6-1 GHz 10 W amplifier 10

11 F) Data for GaN 6-1 GHz module 11