A Study On TX Leakage In 4G LTE Handset Terminals

1. 1

2. By Criterion
2

3. By Criterion
3

4. By Criterion
Duplexing
 A typical transceiver architecture of a 4G cellular phone
is as shown below[1]:
4

5. By Criterion
Duplexing
 Duplexing is required for the simultaneous
transmission and reception of signals[1].
 There are two types of duplexing in use today;
time division duplexing (TDD), where the base-station
and terminal transmit in turn, and frequency division
duplex (FDD) where simultaneous transmission
occurs[1].
5

6. By Criterion
Duplexing
 FDD uses two closely spaced sub-bands for
simultaneous up-link transmission and down-link
reception.
 The problem is that the transmitter power
amplier (PA) amplies both the desired transmitter (Tx)
signal as well as the noise over a wide frequency range.
 Some of this noise falls in the receiver (Rx) band
and desensitises the receiver. Duplex filters separate
out the Tx and Rx frequencies[1].
6

7. By Criterion
Duplexing
 The band pass filter in the transmitter path
(BPFTx) passes the Tx signal through to the antenna but
stops the transmitter noise.
 The band pass filter in the receiver path (BPFRx) allows
the incoming Rx signal to enter the receiver but stops
the strong Tx signal from overloading (blocking) the
receiver circuits[1].
7

8. By Criterion
8

9. By Criterion
Duplexer
 A duplexer consists of two filters, TX filter and RX filter.
Thus, when TX signal leakages to RX port through
duplexer, there will be two frequency responses[3].
PA Transceiver
TX Filter
RX Filter
Duplexer
TX Leakage
TX Filter RX Filter
9

10. By Criterion
Duplexer
 By combining the frequency response of TX filter with
which of RX filter, we’re able to get the TX-RX
isolation[1,3].
 As shown above, the isolation is at least -50 dB, it
indicates that the duplexer attenuates the TX signal that
leakages to RX port through the duplexer at least 50 dB.
 Thus, the isolation of duplexer should be as large as
possible or else the sensitivity may degrade[1].
10

11. By Criterion
How does TX signal interfere RX signal
 In addition to poor isolation of duplexer, the TX signal
may contaminate RX signal through three mechanisms
as well :
 Poor shielding
 Non 50Ω impedance of TX, RX, and ANT port
 Poor layout
11

12. By Criterion
Non 50Ω impedance of ANT port
 Because objects (e.g. hands, head etc.) in the near-field
of the antenna affect its impedance, the matching
condition at the antenna port of the duplexer are
influenced by the near-field distortion, which leads to a
variant Tx-Rx isolation[30].
12

13. By Criterion
Non 50Ω impedance of ANT port
 As shown below, the isolation depends on the
impedance from ANT port to connector[4].
 Therefore, make sure the impedance is 50Ω or else the
isolation may become poor.
PA
Duplexer
Impedance
Transceiver
13

14. By Criterion
Non 50Ω impedance of TX- and RX port
 The frequency response depends on the impedance of
input and output port of a filter, as shown below:
50Ω 50Ω
Non 50Ω Non 50Ω
IL(dB)
 That’s why the impedance from ANT port to connector
affects isolation because it affects both the frequency
response of TX filter and RX filter, thereby changing
isolation. 14

15. By Criterion
Non 50Ω impedance of TX- and RX port
PA
Duplexer Impedance
Transceiver
Impedance
 So the impedance from duplexer RX port to transceiver
affects the frequency response of RX filter. Similarly,
the impedance from PA output to duplexer TX port
affects the frequency response of TX filter.
 If the frequency response of TX filter or RX filter alters,
the isolation alters as well.
 Therefore, make sure the TX port and RX port
impedance are both 50Ω(If Rx is single-end) or else the
isolation may become poor.
15

16. By Criterion
Poor layout
 The proper layout of duplexer is as shown below[2]:
ANT
(Tx/Rx)
TX RX
isolation
Aggressor
Victim
 Make the GND among TX, RX, and ANT port as solid as
possible to enhance the isolation among the three ports.
16

17. By Criterion
Poor layout
 Take AVAGO ACMD-7612 for example, the manufacturer
already makes all of its GND pins become a whole solid
GND[5].
 Thus, if we make the GND among TX, RX, and ANT port
solid in PCB, the isolation can improve further.
17

18. By Criterion
Poor layout
 In addition to solid GND, the GND vias should be as
many as possible or else the TX signal may couple to
RX signal through GND without enough vias[2].
ANT Port
RX Port
TX Port
ANT Port
TX Port
RX Port
18

19. By Criterion
Poor layout
 The current consumption of LTE PA is large with max
power, and the high temperature may alter the
duplexer’s frequency response including isolation[2,6].
PA Dup
 Thus, we need numerous GND vias to spread the
thermal issue as well.
19

20. By Criterion
Poor layout
 In addition to duplexer’s isolation, it is important to
make TX, RX, and ANT traces keep away from each
other or else the TX signal may couple to RX signal as
well.
Keep away from each other
TX Trace
RX Trace
Keep away from each other
ANT Trace
RX Trace
Keep away from each other
TX Trace
ANT Trace
ANT
(Tx/Rx)
TX RX
isolation
Aggressor
Victim
20

21. By Criterion
21

22. By Criterion
 Thus, if the grounding of shielding can is poor, the TX
signal on shielding can will interfere RX signal by
means of reflection.
Poor shielding
 The PA will couple TX signal to shielding can. In other
words, there will be TX signal on shielding can.
PA Dup
TX signal
RX Matching components
RX Trace
PA Dup
TX signal
RX Matching components
RX Trace
 But with good grounding, the TX signal on shielding
can will flow to GND completely instead of reflection.
So it’s important make the grounding good.
22

23. By Criterion
Poor shielding
 Besides, some duplexers have metal coat, which
should be GND in PCB if the layout is good and GND
vias are enough.
TX Signal
 In other words, even though there is residual TX signal
on the metal coat, which will flow to GND completely.
TX Signal
23

24. By Criterion
Poor shielding
 Nevertheless, if the layout isn’t good or GND vias are
not enough, the metal coat will become a radiator,
which radiates TX signal to shielding can.
 As mentioned above, if the grounding of shielding can
is poor, the TX signal on shielding can will interfere RX
signal by means of reflection.
TX Signal
RX Matching components
RX Trace
TX signal
24

25. By Criterion
25

26. By Criterion
Impact of Tx Leakage on the Receiver
 The high power Tx signal can desensitize the receiver
through several mechanisms[1]:
 Gain compression
 RX Band Noise
 Inter Modulation
 Cross Modulation
 Reciprocal Mixing
 DC Offset
26

27. By Criterion
Gain compression
 Take Qualcomm WTR3925 for example, it has six gain
modes, which result in different gain and linearity
individually, as shown below:
27

28. By Criterion
Gain compression
 When the mobile phone is at the cell boundary, the RX
signal from base station is extremely weak due to long
distance. Similarly, the TX signal from mobile phone is
very large to maintain communication quality[2,24].
Strong TX
Weak RX
28

29. By Criterion
Gain compression
 Since the desired signal is extremely weak, the LNA
gain must be kept high to lower whole noise figure to
achieve acceptable sensitivity[2].
29

30. By Criterion
Gain compression
 But, as shown above, the highest gain leads to worst
linearity.
 Besides, as mentioned above, the TX signal is very
strong.
 Thus, with LNA’s worst linearity and strong TX signal, if
the duplexer’s isolation is not large enough, the LNA
may be in compression, i.e. saturation[2].
24 dBm
PA
Transceiver
27 dBm
P1dB = -20 dBm
Post Loss = 3 dB
TX @ LNA input
= -18 dBm
Iso = 45 dB
TX@LNA Input
Isolation 30

31. By Criterion
Gain compression
 As shown below, strong TX signal can drastically
compress LNA’s gain. The large the TX signal is, the
more the LNA’s gain will decrease[2].
31

32. By Criterion
Gain compression
 According to the Friis formula :
before achieving minimum noise figure, the larger the
LNA’s gain is, the lower the noise figure will be[2].
 Thus, a reduction in LNA’s gain results in an increment
in noise figure, thereby aggravating the sensitivity.
LNA Gain
Noise Figure
Minimum Noise Figure
TX@LNA Input
Noise Figure
32

33. By Criterion
Gain compression
 As shown right :
We can derive the formula :
Power Post-Loss PA Output
27324
Conducted Power (dBm) = PAoutput(dBm) – Post-loss(dB)
 Therefore, the more the post-loss is, the larger the PA
output will be.
PAoutput
Post-Loss
33

34. By Criterion
Gain compression
 As shown below, we can derive the formula :
TX@LNA input (dBm) = PAoutput(dBm) – Isolation(dB)
TX @ LNA input
= -18 dBm
24 dBm
27 dBm
PA
Transceiver
Iso = 45 dB
 Thus, with constant isolation, the larger the PA output
is, the larger the TX@LNA input will be.
PAoutput
TX@LNA Input
34

35. By Criterion
Gain compression
 Combining the two concepts mentioned above, we can
realize that the more the post-loss is, the larger the
TX@LNA input will be. So we should keep post-loss as
small as possible to mitigate the TX@LNA input.
 Moreover, as mentioned earlier, more post-loss leads to
higher PA output power, thereby increasing current
consumption and aggravating ACLR. Both the two
influences are harmful to sensitivity.
35

36. By Criterion
DC Offset
 Take BGA7L1N6 for example, which is a LTE LNA
supporting Band5(869 – 894 MHz). As shown below, the
LNA amplifies the frequency ranging from 250 – 2000
MHz[29].
 In other words, TX frequency(824 – 849 MHz) will be
amplified about 13 dB by this LNA as well.
36

37. By Criterion
 In this case, with -23 dBm TX signal at LNA input, the
TX signal at LNA output will be -10 dBm
(-23 dBm + 13 dB = -10 dBm).
 Thus, in Rx path, the mixer’s linearity requirement is
more stringent than LNA because TX signal at mixer
input is larger than which at LNA input[24].
0 Hz
RX
TX
0 Hz
RX
0 Hz
RX
TX
-23 dBm -10 dBm
G = 13 dB
DC Offset
37

38. By Criterion
DC Offset
 In addition to gain compression, DC offset is the
nonlinear effect as well. Thus, the strong TX signal may
saturate mixer, thereby producing DC offset due to
mixer’s nonlinearity[2].
 For direct-conversion receiver, the RX signal down-
converts to baseband signal directly. So the DC offset
due to mixer’s nonlinearity may raise the noise floor of
down-converted baseband signal, thereby aggravating
sensitivity[2].
0 Hz
RX
TX
0 Hz
RX
DC Offset
38

39. By Criterion
DC Offset
 As mentioned above, when the mobile phone is at the
cell boundary, the RX signal is extremely weak and TX
signal is very large.
Strong TX
Weak RX
Strong Blocker
 Besides, there is a strong blocker presence if another
base station in another cell is near mobile terminal
[2,24].
39

40. By Criterion
DC Offset
 In this case, there will be blocker and Tx signal in Rx
path simultaneously. And perhaps both of them will be
amplified by LNA[24].
 Thus, there will be two DC Offset products due to
mixer’s nonlinearity. So the total DC Offset is larger,
thereby aggravating sensitivity more.
0 Hz
RX
TX Blocker
0 Hz
RX
0 Hz
RX
DC Offset(Saturation)
DC Offset due to TX(Saturation)
DC Offset due to Blocker(Saturation)
Combine
TX Blocker
G = 13 dB
-23 dBm -10 dBm-40 dBm -27 dBm
40

41. By Criterion
DC Offset
 Similarly, the DC offset may also appear at LNA output
due to LNA’s nonlinearity. But in the stage, the RX
signal is still in RF frequency, so we can remove DC
offset at LNA output by means of DC block.
 But RX signal is already down-converted to baseband
signal at mixer output, DC block will remove both down-
converted baseband signal and DC offset. So DC offset
due to mixer’s nonlinearity is more troublesome.
0 Hz
RX
TX Blocker
0 Hz
RX
TX Blocker
0 Hz
RX
DC Offset(Saturation)
DC Offset due to TX(Saturation)
DC Offset due to Blocker(Saturation)
Combine
41

42. By Criterion
RX Band Noise
 As mentioned above, the transmitter power
amplifier (PA) amplies both the desired transmitter (Tx)
signal as well as the noise over a wide frequency
range[1].
PA
Transceiver
 Especially, Band12 is the worst case
because its duplex spacing(30 MHz)
and band gap(12 MHz) are
extremely narrow[8].
PA input
PA output
RX Signal
30 MHz 42

43. By Criterion
RX Band Noise
 Besides, the RX band noise is not only from transceiver
, but also from PA itself[8].
 For example, we choose Qualcomm WTR3925 as
transceiver, and SKY77643-11 for PA[7,9].
WTR3925
SKY77643-11
WTR3925 SKY77643-11
RX Band Noise -150 dBm/Hz -130 dBm/Hz
Gain 30 dB
43

44. By Criterion
 The total RX band noise at PA put is -119.6 dBm/Hz
RX Band Noise
 With PA’s gain, the RX band noise from WTR3925 is
-120 dBm/Hz(-150 dBm/Hz + 30 dB gain) at PA output[8].
 The RX band noise from PA itself is -130 dBm/Hz[9].
44

45. By Criterion
RX Band Noise
 Assuming the isolation is 50 dB[31], then the RX band
noise at LNA input = -119.6 dBm/Hz – 50 dB
= -169.6 dBm/Hz
 Since the thermal noise floor is -174 dBm/Hz, the actual
RX noise floor is
 In other words, RX band noise make sensitivity raise
about 5.75 dB[32].
WTR3925
SKY77643-11
Actual RX band noise floor = -168.25 dBm/Hz
Thermal noise = -174 dBm/Hz
5.75 dB
Iso = 50 dB
45

46. By Criterion
RX Band Noise
 Thus, the larger the isolation is, the less the de-sense
will be. The isolation should be at least 50 dB[1].
 As mentioned above, if we want to improve the
isolation further, we ought to avoid the following
situations :
 Poor shielding
 Non 50Ω impedance of TX, RX, and ANT port
 Poor layout
46

47. By Criterion
RX Band Noise
 Besides, LTE requires the Tx noise
leaking into the Rx band to be <-183dBm/Hz[1].
WTR3925
SKY77643-11
RX original noise floor = -169 dBm/Hz
RX band noise = -183 dBm/Hz
RX actual noise floor = -168.83 dBm/Hz
0.17 dB
Iso = 50 dB
 Take previous case for example, -183 dBm/Hz Rx band
noise makes Rx noise floor raise merely 0.17 dB, which
is an acceptable level[1].
47

48. By Criterion
RX Band Noise
 As mentioned above, the total RX band noise comes
from transceiver and PA.
 Thus, we should make the impedance between
transceiver and PA be closer to 50Ω to improve
DA(Driver Amplifier) linearity, thereby mitigating RX
band noise from transceiver[10].
Transceiver
DA
48

49. By Criterion
RX Band Noise
 Similarly, we should make the impedance between PA
and connector be closer to 50 Ω to improve PA linearity,
thereby mitigating RX band noise from PA[10].
 Besides, as mentioned above, the frequency response
of TX filter is related to the impedance between PA and
connector. So making the impedance closer to 50 Ω
is optimizing the duplexer’s isolation as well.
PA
49

50. By Criterion
RX Band Noise
 In terms of ACLR, mitigating RX band noise is just
optimizing ACLR. So the ACLR should meet
specification to achieve acceptable Rx band noise[22].
 Besides, mitigating RX band noise from transceiver is
also optimizing ACLR at PA input, thereby improving
ACLR at PA output further[10].
50

51. By Criterion
RX Band Noise
 As mentioned above, larger PA post-loss leads to larger
PA output power, thereby aggravating TX@LNA input
and ACLR. So it proves again that to lower the PA post-
loss is beneficial for TX de-sense issue[10-12].
PAoutput
Post-Loss
PAoutput
TX@LNA Input
Post-Loss
TX@LNA Input
51

52. By Criterion
Reciprocal Mixing
 During down-conversion in a receiver, reciprocal mixing
of the phase noise of a local oscillator (LO) with an
unwanted TX signal may deposit additive noise on top
of the RX signal, thereby aggravating sensitivity[13,16].
RX
TX TX
RX
Phase Noise
 The undesirable reciprocal mixing may be mitigated by
implementing some skills that can minimize phase
noise of a LO[13].
52

53. By Criterion
Reciprocal Mixing
 As mentioned above, chances are that there will be
blocker and Tx signal in Rx path simultaneously.
Phase Noise
RX
TX Blocker
RX
TX Blocker
 Consequently, the phase noise of a LO with TX signal
and blocker may deposit stronger additive noise on top
of the RX signal, thereby aggravating sensitivity
more[13,16,17].
53

54. By Criterion
Reciprocal Mixing
 Firstly, as shown below, these areas marked red should
be kept out because these areas are VCO related
circuits. Otherwise, the parasitic effect may aggravate
the phase noise of VCO.
54

55. By Criterion
Reciprocal Mixing
 Secondly, take Qualcomm WTR1605(L) for example, the
related pins are as below[15] :
55

56. By Criterion
Reciprocal Mixing
 For these VCO, PLL, LO, and synthesizer pins, if their
Vdd is too low, the phase noise will aggravate[14-15].
Phase Noise
 Besides, even though the Vdd is large enough, large IR
drop leads to low Idd, thereby aggravating phase noise.
As shown above, IR drop allowed at any WTR1605(L)
pin is 20mV. If IR drop is larger than 20mV, the phase
noise will aggravate[14-15].
56

57. By Criterion
Reciprocal Mixing
 In addition to low Vdd and Idd, large ripple in voltage
supply will contribute to phase noise as well[15].
Ripple
Voltage
Time
 As shown below, larger value of decoupling capacitor
results in lower phase noise due to better
decoupling[15].
57

58. By Criterion
Reciprocal Mixing
 Thirdly, instead of sharing a common ground flood with
all RF transceiver ground pins, the opposite grounding
method is to keep multiple subgroupings separate from
each other until they converge on the main PCB ground
plane, especially for VCO, PLL, LO, and synthesizer
GND pins[15].
58

59. By Criterion
Intermodulation
 TX signal leaks into not only RX path, but also LO port
due to parasitic coupling[16].
 Thus, TX signal will self-mix and create a DC offset
signal at mixer output, thereby aggravating sensitivity.
This phenomenon is called self-mixing[1,16].
 Because the product of self-mixing is due to (FTX - FTX),
we are able to regard it as 2nd order
intermodulation(IMD2) as well[16,24].
0 Hz
RX
TX
0 Hz
RX
IMD2(Self-Mixing)
0 Hz
RX
TX
TX signal
59

60. By Criterion
Intermodulation
 As mentioned above, chances are that there will be
blocker and Tx signal in Rx path simultaneously.
 In this case, there will be two IMD2 products due to
(FBlocker - FBlocker) and (FTX - FTX) from self-mixing. So
the total DC Offset is larger, thereby aggravating
sensitivity more.
TX signal
0 Hz
RX
TX Blocker
0 Hz
RX
TX Blocker
0 Hz
RX
IMD2(Self-Mixing)
Blocker
IMD2 due to TX(Self-Mixing)
IMD2 due to Blocker(Self-Mixing)
Combine
60

61. By Criterion
Intermodulation
 Besides, Tx signal and blocker will produce IMD2
(FTX - FBlocker) due to mixer’s nonlinearity.
 Although the IMD2 is not at 0Hz in spectrum, the
bandwidth(BW) of the IMD2 at baseband can be up to
twice the blocker’s or the Tx signal’s BW[16].
 If Tx signal and blocker are both close to Rx signal in
spectrum, the IMD2 near 0Hz will partially or fully
interfere Rx signal with its twice BW, thereby
aggravating sensitivity[16].
0 Hz
RX
TX Blocker
0 Hz
RX
TX Blocker
0 Hz
RX
IMD2
61

62. By Criterion
Intermodulation
 Similarly, Tx signal and blocker will produce IMD3
(2FTX - FBlocker) due to LNA’s nonlinearity.
 Although the IMD3 is not at Rx frequency in spectrum,
the BW of the IMD3 can be up to triple the blocker’s or
the Tx signal’s BW[16].
 If Tx signal and blocker are both close to Rx signal in
spectrum, the IMD3 near Rx frequency will partially or
fully interfere Rx signal with its triple BW, thereby
aggravating sensitivity[16].
0 Hz
RX
TX Blocker
0 Hz
TX Blocker
0 Hz
RX
IMD3
RX
IMD3
62

63. By Criterion
Intermodulation
 If the blocker’s frequency is nearly twice the Tx signal
or Rx signal, Tx signal and blocker will produce IMD2
(FTX - FBlocker) near Rx frequency due to LNA’s
nonlinearity[18].
0 Hz
RX
0 Hz
RX
TX Blocker
0 Hz
RX
TX Blocker
IMD2 IMD2
 Similarly, although the IMD2 is not at Rx frequency, the
IMD2 near Rx frequency will partially or fully interfere
Rx signal with its twice BW, thereby aggravating
sensitivity.
63

64. By Criterion
Intermodulation
 If the blocker’s frequency is nearly twice the Tx signal
or Rx signal, Tx signal and blocker will produce IMD2
(FTX - FBlocker) near Rx frequency due to LNA’s
nonlinearity[18].
0 Hz
RX
0 Hz
RX
TX Blocker
0 Hz
RX
TX Blocker
IMD2 IMD2
 Similarly, although the IMD2 is not at Rx frequency, the
IMD2 near Rx frequency will partially or fully interfere
Rx signal with its twice BW, thereby aggravating
sensitivity.
64

65. By Criterion
Crossmodulation
 Cross modulation(XMD) occurs when a number of
tones are applied to a nonlinear system such as
amplifier. And as long as one of these tones is
amplitude-modulated.
 Intermodulation occurs when a number of tones are
applied to a nonlinear system such as amplifier
regardless of whether these tones are amplitude-
modulated or not [33,34].
65

66. By Criterion
Crossmodulation
 In actual FDD-LTE system, there might be TX signal and
blocker on the RX path simultaneously.
66

67. By Criterion
Crossmodulation
 ,With LNA’s nonlinearity, TX signal and blocker might
produce IMD and XMD products, which interfere with
received signal indeed.
67

68. By Criterion
Crossmodulation
 ,The XMD formula is as shown below:
it indicates that XMD increases by 2dB as the Tx
leakage power increases by 1dB(i.e. duplexer isolation
decreases by 1dB) [33].
68

69. Reference
[1] A TUNABLE LOW-ISOLATION DEVICE FOR ADAPTIVE DUPLEXERS
[2] SAW-less Direct Conversion Receiver Consideration, slideshare
[3] ACMD-7614 UMTS Band 1 Duplexer, AVAGO
[4] Radio Front End for Enhanced Data Rate at Cell Edges, RFMD
[5] ACMD-7612 Miniature UMTS Band I Duplexer, AVAGO
[6] Balanced RF Duplexer with Low Interference Using Hybrid BAW Resonators
for LTE Application
[7] WTR39xx Wafer-level RF Transceiver Device Specification, Qualcomm
[8] A Study on Low Rx-Band Noise Power Amplifier for Reconfigurable RF Front-End Circuit,
Murata
[9] SKY77643-11 Multimode Multiband Power Amplifier Module, SKYWORKS
[10] GNSS De-sense by IMT and PCS DA Output, slideshare
[11] Understand and characterize envelope-tracking power amplifiers
[12] How to solve ACLR issue, slideshare
[13] RECIPROCAL MIXING NOISE CANCELLATION SYSTEM, US Patent, Broadcom
[14] A Study of Phase Noise in CMOS Oscillators
[15] GPS RF FRONT-END CONSIDERATIONS, slideshare
69

70. [16] Effective IM2 estimation for two-tone and WCDMA modulated blockers in zero-IF
[17] How to Combat the Many Causes of Radio Sensitivity Degradation
[18] IP2 and IP3 Nonlinearity Specifications for 3G/WCDMA Receivers
[19] Low-Noise Active Cancellation of Transmitter Leakage and Transmitter Noise in Broadband
Wireless Receivers for FDD/Co-Existence, IEEE
[20] An Active Transmitter Leakage Suppression Technique for CMOS SAW-Less CDMA Receiver,
IEEE
[21] Digitally Assisted IIP2 Calibration for CMOS Direct-Conversion Receivers, IEEE
[22] A PA-Noise Cancellation Technique for Next Generation Highly Integrated RF Front-Ends,
IEEE
[23] SAW-Less Analog Front-End Receivers for TDD and FDD, IEEE
[24] A CMOS Transmitter Leakage Canceller for WCDMA Application, IEEE
[25] An Integrated CMOS Passive Self-Interference Mitigation Technique for FDD Radios, IEEE
[26] Integrated Wideband Self-Interference Cancellation in the RF Domain for FDD and Full-
Duplex Wireless, IEEE
[27] Second-Order Intermodulation Mechanisms in CMOS Down-converters, IEEE
[28] BGU8H1 LTE LNA evaluation board, AN11514, NXP
70

71. [29] Single Band LTE LNA Using BGA7L1N6 Supporting Band-5 (869- 894 MHz) Using
0201 Components, BGA7L1N6, Infineon
[30] Baseband Analysis of Tx Leakage in WCDMA Zero-IF-Receivers
[31] B7931 SAW Duplexer, LTE Band 12 + 17, TDK
[32] Link Budget Analysis for RF Front-end Design, Qualcomm
[33] CDMA Zero-IF Receiver Consideration, Slideshare
[34] Cross Modulation and Intermodulation in Amplifiers at High Frequencies, IEEE
71