# A Space-Borne Ka-Band Tile-Type Phased Array Transmitter Module Based on HTCC Technology
## 4 Test Results and Discussion  
A Ka-band miniaturized transmitter SIP module is designed based on the HTCC process. The external interface of this component is in the form of BGA solder balls, making it convenient for surface mounting arrays. It has four-channel phase shifting, attenuation, and amplification functions, and the volume is only 12.2 mm \(\times\) 12.2 mm \(\times\) 4.3 mm. Four PAs are mounted at the front side of the module, as shown in Figure 12a, and the four-channel multi-functional chip is assembled at the back side of the module, as shown in Figure 12b. The performance of the transceiver module is tested by the setup shown in Figure 13. The HTCC module is mounted on the test fixture to convert the BGA interface of the module into the standard interface of the measurement setup for RF signal and DC power interconnection, as shown in Figure 13a. The module with the fixture is then connected to the measurement setup as illustrated in Figure 13b. The power supply provides \(+5\) V, \(+3.3\) V, and \(-5\) V DC voltage for the active components. The attenuation and phase shifting in each channel are controlled by a serial instruction controller. The gain and the tuning of the attenuation and phase shift are measured by an S-parameter measurement using a vector network analyzer (VNA). The output power is measured by the power meter with a  
Figure 11: The result of the mechanical response simulation. Figure 12: The photos of the transmitter module: (**a**) the front side; (**b**) the back side. single-tone input from a signal generator. The root mean square resolution of amplitude and phase control is acquired via post-processing of attenuation and phase shifting data. The equipment is controlled by a computer for data acquisition. Firstly, the attenuation and phase tuning performances are measured by a VNA. The VNA is calibrated in the frequency range of 26-27 GHz to calibrate the error and losses in the test equipment and RF cable. Then the transmitter module is connected to the test setup, as shown in Figure 13b. The measurement of attenuation and phase shifting is shown in Figure 14a,b. The attenuation can be increased from 0.5 dB to 7.5 dB with a step of 0.5 dB. The phase shift of the module can be adjusted over 360\({}^{\circ}\) with a step of 5.625\({}^{\circ}\). Then 20 transmitter modules with 80 channels were tested to evaluate the consistency of the proposed design. The measurement results in Figure 15 show that the typical value of the attenuation accuracy RMS is better than 0.5 dB, and the typical value of the phase shift accuracy RMS is better than 3\({}^{\circ}\). The transmitting gain is above 26 dB, and the saturated output power is greater than 21 dBm. The inter-channel consistency of output power is better than 0.5 dB. The efficiency of the module is better than 40%. Figure 14: Measurement results of the attenuation and phase tuning performance: (**a**) the attenuation tuning results; (**b**) the phase tuning results. Figure 13: (**a**) Test fixture for the transmitter module. (**b**) Test setup of the transmitter module. A performance comparison is made in Table 6. It can be observed from the table that the proposed module exhibits the highest efficiency with a footprint slightly larger than the T/R module in Ref. [19]. Ideally, the layout of the chips and the routing of the transmission lines can be further optimized to reduce the module size, as the double-sided configuration can provide better space utilization than the single-sided one. Although the output power of the proposed module is smaller than the others in Table 6, it can be improved by using a PA with higher saturation power. The PA in the proposed module is chosen to meet the requirement of the system, as listed in Table 1. The results validate the feasibility of the proposed design for the demand of large-scale active phased array antenna.