A 270-GHz Push-Push Transformer-Based Oscillator Adopting Power Leakage Suppression Technique
Round 1
Reviewer 1 Report
The manuscript has been improved and can be published in its present form.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This is an interesting paper and authors have responded to all of the comments of previous reviewers adequately. I only have one general comment that would be useful to add in the paper to set the context of the paper because many readers from "circuits only" point of view would not see the importance of this paper and that is, there are not many high-frequency sources out there to solve the new terahertz applications requirements. The compound semiconductor that is supposed to provide the active sources from mm-wave to Terahertz and "apparently" they are providing but on a closer look, we will find almost all of them are very poor in DC to RF efficiency. So in that respect, it would be useful if the authors could cite some planar Gunn diodes and Resonant Tunneling Diodes, the two compound semiconductor sources to reach terahertz frequencies and then compare their poor DC to RF efficiencies to your oscillator on a Si chip. This will clearly demonstrate the urgent need for such oscillator and every bit of improvement in the efficiency will be welcome.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
In this paper, the author design and manufacture a THz oscillator with a power leakage suppression technique on a transformer-based oscillator. The output power of the proposed oscillator is -4.5 dBm at 270 GHz. The DC-to-RF efficiency reaches 2.1%. Compare to the conventional design in Ref. 1, there is no obvious improvement, especially in the output power, which is one of the most important targets of a newly designed source. There is no direct comparison of measurable results for the conventional and proposed oscillators. It is really hard to claim that the proposed “power leakage suppression” is an effective way to improve the oscillator further. More careful and detailed comparisons are needed. Besides, the introduction doesn’t provide sufficient background. The manuscript doesn’t include enough relevant references. The result should be compared with other types of design. The discussion in the paper is limited in two similar design with a limit difference. The result will not attract a wide attention from readers. I cannot recommend the publication in the journal “Electronics”.
Reviewer 2 Report
A modified topology for a push-push transformer-based oscillator is proposed, eliminating the connection between primary and secondary ports. The modified topology technique reduces the power loss due to an unwanted leakage path unnecessary for the oscillator operations at second harmonic frequency, thus with a little increase in the DC-to-RF power conversion efficiency.
The manuscript is sufficiently well written and organized. The theory, the simulations and the experimental results are sufficiently convincing. Doubts remain about the real importance of the scientific contribution of this work.
Comments:
- In the Introduction the reader has no clues on the real world applications of this kind of oscillators (too vague "....various applications, such as imaging, spectroscopy and communication..."!), taking special consideration of the low power generated by these oscillators and their very low efficiency.
- A more detailed description of the working principle of both the circuits is required. In general, please spend some words to explain to non-specialist readers how this circuits work. For example, please clarify the circuit transformation in Figure 2. Under which assumptions it is solved the twisted topology of the loop (Lg, Lg, Lgs, Lgs)? In Fig. 1 it is not clear the oscillator current path.
- Is the oscillator working at f0 or at 2f0 during its normal operation? Please clarify and justify this issue.
- Please provide details of the circuit simulator used (see row 63 and 70).
- please provide further details about the chip realization: the technological and experimental setup description should be detailed enough to allow anyone to reproduce the sam experiment elsewhere.
- What about frequency stability and jitter of the proposed oscillator?
Minor issues:
- bo in (6) is the same as bout 2 rows below?
- Along the manuscript, please carefully put always a space between values and units (see eg 260GHz at row 69 and 266OHM at row 70 and 72).
