TECHNICAL APPRACH

FOR

L BAND (1.28 TO 1.4 GHz) SOLID STATE POWER AMPLIFIER

(SSPA)

NAVANIDHI ELECTRONICS PVT. LTD. Plot No.21, IDA Mallapur, I.E, NACHARAM

HYDERABD – 500076 Phone: 040 – 27155843, 27157295

Fax – 27170244 Website – www.navanidhi.com

Technical Approach

To meet the required specification, the L band solid state power amplifier is realized as per the below block diagram.

Technical Approach for 4.0KW (PULSED) PA

To meet the required specification, the L band solid state power amplifier is realized as To meet the required specification, the L band solid state power amplifier is realized as

1. Directional coupler

The input level +10dBm is fed to the directional coupler (DC), the purpose of the DC is to monitor the input level to the power amplifier. The output level of the DC is +7.0dBm.

a. Make : M/S Mini Circuits b. Part No : DBTC-7-152+ c. Frequency : 10-1500MHz d. Main line loss : 3.0 dB Max. e. Coupling : 7.0 dB f. Operating temperature : -40°C to +85°C

2. Limiter The output of the DC (+7dBm) is fed to the limiter, it will control the input power

variation (from 0dBm to +30dBm) to limit the 0dBm output, it will provide the protection to input over drive.

a. Make : M/S Mini Circuits b. Part No : RLM-23-1WL+ c. Frequency : 100-2500MHz d. Insertion loss : 0.7dB e. Output power : 0dBm Typ. @ 30dBm f. Operating temperature : -40°C to +85°C

3. Radio frequency switch (R.F.S)

The output of the limiter 0dBm is fed to the RFS, the purpose of the RFS is to switch OFF the RF input to the amplifier whenever the VSWR, thermal fault or both appears. It has 1.0dB loss. The output level of the RFS is -1.0dBm.

a. Make : Hittite b. Part No : HMC349MS8G c. Frequency : DC-4GHz d. Isolation : 60dB e. Insertion loss : 1.0dB f. Input power handling : 30dBm g. Operating voltage : +5V DC h. Operating temperature : -40°C to +85°C

4. Digital attenuator (D.A) The output of the RFS (-1.0dBm) is fed to the digital attenuator (D.A). The purpose of

the D.A is to maintain the output power (amplitude) matching (balancing) among the RF channels. The output level of the D.A is -7.0dBm.

a. Make : Hittite b. Part No : HMC472LP4 c. Attenuation range : -0.5 to -31.5dB d. Insertion loss : 1.8dB Max. e. Operating voltage : +5V DC f. Operating temperature : -40°C to +85°C

5. Phase shifter (P.S) The output of the D.A (-7.0dBm) is fed to the phase shifter (P.S). The purpose of the

phase shifter is to maintain the phase balance among the RF channels. The phase can be adjusted from 0° to 360° by varying the control voltage of the phase shifter.

a. Make : Mini Circuits b. Part No : SPHSA-152+ c. Insertion loss : -4.0dB d. Phase range : 0° to 360° e. Control voltage : 0-15V f. Operating temperature : -40°C to +85°C

6. Pre amplifier The output of the P.S (-11.0dBm) is fed to the pre amplifier. The gain of the pre amplifier

is +21dB. The output of the pre amplifier is +10dBm. Power handling capability (P1dB compression) is +18dBm.

a. Make : Mini circuits b. Part No : MNA 6+ c. Frequency : 0.5 to 2.5GHz d. Gain : 21dB e. Operating voltage : +5V DC f. Operating temperature : -40°C to +85°C

7. Driver amplifier 1 The output of the pre amplifier (+10dBm) is fed to the driver amplifier 1. The gain of the

driver amplifier1 is +25dB. The output of the driver amplifier1 is +35dBm. Power handling capability is 10W.

a. Make : Freescale semiconductor b. Part No : MRF6V10010NR4 c. Frequency : 960 to 1400MHz d. Output power : 10W e. Gain : 25dB f. Operating voltage : 50V DC

8. Driver amplifier 2 The output of the driver amplifier1 (+35dBm) is fed to the driver amplifier2. The gain of

the driver amplifier2 is 18dB.The output of the driver amplifier2 is +53dBm. Power handling capability is 330W.

a. Make : Freescale semiconductor b. Part No : MRF6V14300HR3 c. Frequency : 1.2 to 1.4 GHz d. Output power : 330W e. Gain : 18dB f. Operating voltage : 50V DC

9. High power amplifier (H.P.A) The HPA consists of 1:3 power divider (1No), 1:4 power divider (3 No’s), basic power

modules (12 No’s), 1:4 Power combiner (3 No’s) and 1:3 power combiner (1 No). The output of the driver amplifier2 (53dBm) is fed to the BPM’s 1 to 12 through 1:3 and 1:4 (3 No’s) power dividers. It is realized by BLL6H1214-500 LDMOS of NXP Semiconductor. The gain of each module is 15dB, its operating voltage is +50V DC. Power handling capability is 500W. It is working in L Band 1.2 to 1.4 GHz only. The main reason to select this device is to get the very low harmonic levels and very less rise time (20nsec) and fall time (6nsec). This device is ment for radar application only. The outputs of 12 BPM’s are combined through 3 no’s of 1:4 and 1.3 power combiners. This output is fed to the output port of the amplifier through DDC, which is realized by micro strip line technique. The loss of the DDC is 0.2dB. The coupling of the DDC is 40dB (FWD&RFL) and directivity is 15dB. The purpose of the DDC is to get the output sampled forward and reflected powers, which are required for the monitoring and controlling purposes.

10. Basic power module (B.P.M) a. Make : NXP semiconductor b. Part No : BLL6H1214-500 c. Frequency : 1.2 to 1.4 GHz d. Output power : 500W e. Gain : 17dB f. Operating voltage : 50V DC

SSPA SSPA will be realized with 16 no’s of 4.0KW amplifier modules and one no of 1:16 power

divider module, these modules will be placed in the mechanical rack in 2X8 matrix to maintain the required dimensions [1550(L) X 700(B) X 410(H)].

Ø To get the calibration and phase matching of each channel, phase shifter is provided.

Ø To get the gain matching of the each channel, digital attenuator is provided. Ø BITS facility is provided for VSWR, thermal and full power output at front panel

LED indication for each channel, and also provision for BITS (other than calibration output) will be provided through remote interface.

Ø MIL Grade connectors for input/output, power supply and data interface is used. Ø SSPA/individual modules will meet MIL STD 810G. Ø Provision for forced air cooling for each channel is provided.

Control & Monitoring Circuit

Control and Monitoring circuit is a system controller assembled in 4KW RF POWER AMPLIFIER designed to interface with Remote System. It controls the operation of the Power amplifier based on Remote System interface commands and updates operation status on demand. It also monitors the amplifier operation, and generates the fault indications, if any fault occurs. The Control circuit design is based on Microchip’s Advanced PIC18 series Microcontroller.